One of my players thinks it's the best way to run D&D. 

Is this true or are there issues with it?

There are so many issues with it that it almost killed the game.

/exaggeration (maybe)

Your player, if they aren't trying to prank you, is in the vast minority. Most didn't like 4e. I personally never played it, but that was mainly because of the negative reviews I'd heard of it.

Every edition has issues. The current edition has issues, next year’s revised version will have issues, it’s inevitable.

I never played 4e, I skipped that edition personally. But from what I understand from everything I’ve read or heard about it is that it wasn’t really a bad game, I just wasn’t really D&D either. From what I’ve gathered, it was simply too big of a departure from what makes D&D feel like “D&D,” and so people rejected it. Had it been called something completely different it might very well have been relatively popular. Who can say?

4e is a really good tactical fantasy combat game. There are tons of things it does that I wish 5e did. But I agree with Sposta that as a whole, it "felt" less like D&D.

What's really funny to me is that 4e is what drove a lot of players to Pathfinder, and now Pathfinder 2e is way more like 4e than any other edition of D&D is.

A lot of criticism about 4E was about how "video gamey" it felt, and honestly there's some truth to that: the classes were given rigidly defined roles: Leader (buffs and heals allies), Tank/Defender (blocks enemies), Striker (inflicts high damage to single targets), or Controller (manipulates the battlefield with area effecting abilities).  There certainly was some feeling like it was attempting to be a tabletop MMO given that you really needed to have one of each of those types in your party, and you needed to constantly grind for better gear because monster stats improved faster than player stats as you leveled.  On the other hand, it's also the only edition that's ever gotten any decent balance of power levels between the classes.

The other big thing I've heard about 4e was that there was little roleplay and exploration support compared to other editions.

There wasn't.  It had "utility" powers/spells that got learned at certain levels, but the majority of them were really defensive abilities intended for combat.

Short answer: No.

Slightly longer answer is still: No. It was, perhaps, the most balanced version of the game. It had some new or relevant ideas. Basically, it made everything feel kinda same, and made combat an endless slugfest. It was awful in ways words cannot sufficiently describe. It's the sort of thing you need to try, to fully understand, but when you do, you'll really wish you hadn't. 

It's not great. But it is balanced.

It's probably the best-designed version of D&D.

That said, it did this by really committing to a specific vision, and that cuts out a lot of the ways people play D&D.

If you really like D&D as a game that centers on crunchy tactical combat, then 4e is worth a look. I can't recommend it wholeheartedly because it really benefits from having computer tools to support it, the official ones are no more, and I've never really dug into the unofficial ones. (I ran it by hand, and it was getting to be a strain to level characters and design encounters by the point I wrapped my game, which wasn't that high level.)

Despite what some might say, it's still an RPG, and even added mechanical support for using skills in more complex ways than the usual "make a skill roll", though general consensus was that the skill challenge system was broken. (I believe they issued a revised version.)

There were a lot of things 4e did very well.  

Character customisation was first and foremost, with a progression system that allowed customisation with both feats and ASI.  Feat trees were extensive, and a large number of general, class, and race based feats meant you could take your base character choices and evolve in your own direction (compared to 5e, where, once you choose your race and class, those choices progress mostly on their own with little ability for you to change what decisions are made).

Their magic item system was vastly better than 5e’s—items were levelled and had rarities, rather than the “eh, we’ll only use arbitrary and often wrong-for-their-power rarities” of 5e.

Things like Paragon Paths and Epic Destinies allowed your character to evolve in ways specific to their campaign choices.

There was a “ritual”-like system for Martial characters, giving them some out of combat utility.

These are all elements Wizards should have kept and implemented in 5e—they were not associated with the combat system folks disliked, and easily could have been implemented in a way which would complement the existing 5e design by adding more customisation and options. Unfortunately, Wizards can be a bit reactionary - rather than say “what worked in 4e, let’s use that when we make 5e?” they decided to purge everything about 4e indiscriminately, resulting in the rather linear 5e system we received.  Wizards had an opportunity to bring some more of these elements into the game with the revised edition of 5e—but it looks like they will be playing it safe once again, and refusing to acknowledge some of the benefits 4e has to teach. 

To be fair, what you’re describing is quite crunchy and sounds like it could be somewhat daunting for new players putting together a character; 5e has always aimed for a simple and theoretically efficient character build setup. Which obviously isn’t for everybody, but it’s probably a little reductive to simply declare that they thoughtlessly threw the baby out with the bath water from 4e to 5e.

I played Basic D&D red box, 1E, 2E, 3.X, 4E and 5E and all of them are fantasy roleplaying games that i had a lot of fun with. Roleplay was as much possible in 4E as it was before or after it, it's important to clear this part first because it was oftem to me the most unfounded criticism against 4E. The major difference lied in the mechanical part, and it's aesthetic. Some said it felt more video-gamey to them and the use of powers felt like all classes had spells. But all those attack and utility powers made combat more dynamic in some way. Skill Challenge was also a nice innovation.

I'd day give it a try a few games to see for yourself before too quickly judging the book by its cover. In the end you roleplay, kill monsters, gain treasure and level up along the way!

Quote from The_Ace_of_Rogues >>

To be fair, what you’re describing is quite crunchy and sounds like it could be somewhat daunting for new players putting together a character; 5e has always aimed for a simple and theoretically efficient character build setup. Which obviously isn’t for everybody, but it’s probably a little reductive to simply declare that they thoughtlessly threw the baby out with the bath water from 4e to 5e.

 
None of these systems was too complicated for new players as systems - in fact, most of them were less complicated of additions than selecting spells are (and things like Paragon Paths/Epic Destines were only unlocked past the point someone would be a new player). Frankly, one of 5e’s problems is how much it underestimates the intelligence of new players, resulting in the linear, limited-customisation system that is 5e.  

Also note, 4e did have mechanisms to protect new players - for example level-gating feats and other abilities kept the low-level, new player options limited, and allowed the complexity to grow alongside player experience.

What 4e did wrong though, was take a good system and make it vastly over-complicated through dead content. A new player can easily process 10-15 options (again, that’s fewer than the number of spells we ask them to process), 4e took that to an excess—hundreds of options, most of which were garbage.  It clearly needed streamlining and greater restraint than 4e showed, but holding bad implementation against a better system should be more of an indictment on Wizards’ lack-of-restraint, not of the system itself.

4e was not a flawless game, and at higher levels it turned into a slog of tracking way too many status effects, but for level 1-10 it was a quite fun tactical board game. It did have a problem of not really feeling like 'D&D', however.

Quote from 1d4forlife >>

One of my players thinks it's the best way to run D&D. 

 

Is this true or are there issues with it?

 I will die on the hill that 4th Edition was the best designed version of D&D ever created. Its issues with "higher level play" are the same issues faced by every edition of the game. Its greatest failing was a business decision that allowed most folks to continue on with the previous edition mostly unhindered instead of forcing adoption as the switch from 2nd to 3rd or 4th to 5th required. It was the first and really only edition of D&D that had to compete with its previous version, and entrenched players, entombed under mountains of splat-books, were not interested in changing over, and encouraged to tribify via the rise of internet drama creators.

4th Ed will always hold a place in my heart for having the audacity to cleanly answer the question "What is the highest level spell a 9th level wizard can cast?" with "They can cast 9th level spells because they are 9th level."

I'll agree with many others, 4e did a lot of things right in terms of game design, but it didn't quite feel like D&D. It was very balanced, both in terms of comparing PCs to each other, and a party against a group of monsters. Encounter design was a snap, and making custom enemies was purely math and really easy. But, to me at least, a lot of the characters started to feel pretty same-y. Like everyone had a basic attack that was: 1 weapon damage and push the enemy 1 square, they just found new labels to hang on that power for each class. I know others disagree with this, that's just what it seemed like to me. 

I also didn't love the magic item system, where it was assumed you were going to have a +1 item if a few different item slots by a certain level, and that would go up to +2 by a different level, etc. As a DM, I basically needed to keep a spreadsheet of item drops so I could make sure everyone was correctly powered. (So much so, that I just adopted the low magic variant, where no one gets any magic items, and they just get a flat bonus at the appropriate levels.)

So, yeah, it was really balanced, but turns out that balance removed too much uncertainty and kind of sucked out its soul.

To be fair, the assumption of at least +1 weapons is an unwritten principle of 5e most of the time as well.

Quote from The_Ace_of_Rogues >>

To be fair, the assumption of at least +1 weapons is an unwritten principle of 5e most of the time as well.

 Yeah, but in 5E you're generally functional as long as you've got a magic weapon of any kind while 4E rules basically required you to upgrade or replace your magic weapon every few levels or you'd start to fall behind.

Also, damage output was relatively limited in 4E so fights tended to turn into slogs.

I feel if 4th Ed had been devised with the concept of Bounded Accuracy like we have now, the +X item treadmill would have been rather mitigated.