New DM wondering what books to invest in for new campaigns - 2014 or 2024?

I saw a few threads discussing this, but couldn't quite find advice fitting what I'm looking for. 

I've been playing D&D for almost 2 years now, and am looking into DMing for my first time with a group of mostly 1-st time players I'm looking to indoctrinate into the hobby. In the other campaigns I played in, the DM always could share their content so I never needed to purchase material of my own. However, in these new groups, almost no one has purchased material and I thought it was about time to invest in my own material through D&D Beyond so I can be the one to share it with others. 

My last 2 groups as a player have both stuck with 5e/2014 because that's what the DMs were used to, but I am familiar enough with the game now and have had enough time to see bits and pieces of both that I don't think the transition to 2024 would be difficult. Both would cost me about the same amount as I don't have anything previously purchased for either. I have seen/heard a number of people crapping on 2024 since some people didn't like some of the changes or they believe some things were nerfed.

Is one edition over the other easier to DM with? Is character creation easier with one or the other? Would it be better to purchase the 2014 set and then look into the 2024 updates and just cherry pick what I want to implement? I'm also sort of sheltered within my in-person campaign spheres and don't really stay up to date on upcoming releases unless they somehow cross my radar and are major, so I don't know if there are more potential things releasing in the near future that would also sway this choice. 

Edit - Maybe a better question as well is which books would be best to purchase and use as my "core" for players specifically creating characters on D&D Beyond. If there are certain mechanics from either edition I like better I can easily add that as a homebrew, or I can purchase just digital or just physical versions of the book, rather than investing in both at the moment 

You are mostly going to get opinions on which version of 5e people like better, which may turn into an "edition wars" argument. For me, I can safely say that both have their merits:

5e - I like the character creation flow better and I think having some classes choose their subclass at level 1, rather than 3, made more thematic sense.

5.5e - I think every class is in a better place now than they were in 5e, with some being more heavily tinkered with than others. The DMG is also laid out MUCH better in 5.5e for DMs.

I own both versions and I will probably run every campaign as a 5.5e campaign unless the players have a preference for 5e. None of the points above are deal breakers going the other way, and as you get more experience, you can bring things from... I was going to say "the other edition" but really any edition into whatever you are playing as a base.

Thank you for this! Can I ask what you mean by laid out better? Just organizationally or information flow? 

I agree with Sabin that the 5.5 DMG is a better book than the 5e one. It's difficult to put into words but things are just easier to find, there's a decent glossary for a start so you can look things up quicker, but also things like the 5e book started with creating your own world and set of gods before ever getting to things like how to plan a session. By contrast the new book starts with "What Does a DM Do?" as chapter one followed by advice on planning sessions and actually running the game. It's just an easier book to read and to use as a reference guide. I also think the 5.5 Player's Handbook is a better book for players to read, the language is more intuitive and like the DMG it flows better from one topic to another. I don't necessarily agree with the order they lay out character creation, assigning your background stat boosts before actually deciding your stats is awkward, but on the whole the thing is a better book and I agree with Sabin again that the classes themselves are better tuned.

So I guess I'm saying go with the new books. All my games have switched over and we're all happy with them, whether as DMs or players, apart from one or two rules we preferred from the old rules we've just ported across without much trouble

Ignoring content, generally speaking when a company has a revised/new rule system support for the old starts to diminish and eventually stops.  Probably everything published for the 2014 5e set is already published and "in print".  Anything coming out now and in the future will be written with 2024 5.5e in mind.

You see on the forums there are still people that use 3.5e and 4e.  One can assume you will be able to use 5e for decades to come, however,  what is out there is it.  If there is a new rule set that comes out, it is always advisable to make the switch as then you can receive support and help.  Sticking with an older rule set is less expensive, but becomes more limiting.

I’d say both are really fairly easy to use. I do like the 5.5 model for character generation for new players, as it follows a path that’s more likely to be the way people think about making a character, that is, it starts with choosing a class. In fact, I’d say 5.5 is probably better for new players overall.

But, beyond my opinion, I’d say 5.5 is probably the better investment, if only because new content from here on out will be built to take advantage of the rules. You can use 5.5, and find a 5.0 subclass you really want and then add that in fairly easily. But it doesn’t work as well in the other direction. Using the 5.0 base rules, if there’s a 5.5 thing you want to add, it may work, but there may be some real hiccups. 

Some people always resist change and there are nits to pick with 5.5E as with anything else ever written, but getting into DMing and not going with the most current version of the system would make no sense to me. I'd 100% be buying 5.5E if I was you.

As far as products you need, really the Player's Handbook gives plenty of things for people new to the hobby to choose from. The new DMG is nice and for me the magic items alone make it worth a purchase, but you can certainly run a campaign without it if money is truly tight. I have no feel for how many monsters are available free on DDB, but I would personally find the 5.5E Monster Manual the critical second purchase to make. 

As far as the physical vs digital question, there are pros and cons to both. Lots of DnD fans are old-school and only like printed products, but if you build much of a library that becomes less and less convenient to have with you unless you always play in/near where you keep your books. You mention wanting to use DnD Beyond for the character builder - with that being the case I would definitely get the digital version of the Player's Handbook first and see if you feel like a physical copy is really necessary. If you don't own the PHB on DnD Beyond the character creator is still potentially useful but loses a ton of options unless you want to take the time to type them up as homebrew. Definitely not worth it to me, but some print-lovers would feel differently.

As a DM who only has 5e (2014) books, and has stayed with the 5e 2014 ruleset for my campaigns, I would probably suggest going 5.5e 2024.

From going through the forums and looking at the basic rules for 5.5e, there are some things I like more about 5e for sure (I know it is controversial, but I like the 5e version of Twinned Spell Metamagic more than the 5.5e version, even if the 5.5e version is probably more balanced). Most of that is just personal preference. 5.5e doesn't seem to be worse in any way (except maybe how the Hide rules are an incomprehensible mess, though I'm not sure 5e RAW is actually any better), and in a lot of ways it is objectively better. 5.5e does seem a bit more streamlined (like how things like the Wolf's trip just happens without there being a Saving Throw), but that can be a pro or con depending on how you like your feel of play to be.

The main reason I have stuck with 5e is....money!! I have a good amount invested in 5e materials and the thought of starting over in the current economic environment feels bad. Also, we're in the middle of a campaign currently and I don't feel like switching the ruleset around for the players, especially when some of their subclasses and character options haven't yet been updated to 5.5e. 

But if you are starting fresh, 5.5e seems the way to go. That's what the new content that is going to come out will be for. That's what a lot of online creators are going to shift their content to. That's what will be supported more by D&D Beyond and WOTC in general. If I were starting from scratch right now, I would go in on 5.5e.

It would not even be a thought in my head.  If I am just starting out, 2024.   If you go with 2014, you are going to be stuck back filling your collection for a long time.

For your Core, get the three core 2024 books. The backward compatibility allows you access to the 2014 player options if anyone comes to the table wanting something specific and you will be able to snatch up and use any new thing that catches your eye. Old adventures can also be run pretty easily though if you do that, you will need to tune up monsters a bit to match the increased power of the players.

Just seems like the least amount of work and cost now and later.