So fun fact, you are no longer *literally* invisible with this spell, as the new invisible condition does not directly state that you are now invisible, and WotC did not update things like this spell accordingly. 

You are however *literally* concealed, and effectively as well hidden as someone who actually tries to hide, rolls stealth etc since there is now no hidden condition and the invisible condition is used for both.

You are literally visible with this spell.  It provides no evidence that it provides any effect that makes you 'impossible to see without the aid of magic or a special sense', as the 2014 did.   Look at it this way.  Change the name of the invisibility condition to something else, lets just keep it simple and say 'buffed'. And let's change the spell to 'Get Buffed'.

Get Buffed
Concentration
Level
2nd
Casting Time
1 Action
Range/Area
Touch
Components
V, S, M *
Duration
Concentration 1 Hour
School
Illusion
Attack/Save
None
Damage/Effect
Buffed

A creature you touch has the Buffed condition until the spell ends. The spell ends early immediately after the target makes an attack roll, deals damage, or casts a spell.

Using a Higher-Level Spell Slot. You can target one additional creature for each spell slot level above 2.
* - (an eyelash in gum arabic)

Spell Tags: Buff

Available For: Bard Sorcerer Warlock Wizard Bard Sorcerer Warlock Wizard Trickery Domain


Buffed [Condition]

While you have the Buffed condition, you experience the following effects.

Surprise. If you’re Buffed when you roll Initiative, you have Advantage on the roll.

Concealed. You aren’t affected by any effect that requires its target to be seen unless the effect’s creator can somehow see you. Any equipment you are wearing or carrying is also concealed.

Attacks Affected. Attack rolls against you have Disadvantage, and your attack rolls have Advantage. If a creature can somehow see you, you don’t gain this benefit against that creature.

Thusly... I'm in the middle of combat staring straight into the eyes of my enemy.  I cast 'Get Buffed',  I gain the 'Buffed' condition.  The first effect of being 'buffed' has no bearing, since initiative has already been rolled(in combat).  Me and my equipment are concealed though great.  Now I can't be affected by any effect that requires its target to be seen, unless the the effects creator can somehow see me.  My attacks are affected and I get advantage on attack my attack rolls, and attacks against me have disadvantage, again, unless that creature can see me.  Awesome, I love this so far.  But wait, my enemy can see still see me.  I'm right in front of him, and I've taken no action or gained any effect thus far that states otherwise. So I've just cast a spell, and gained  no benefit from these effects yet.  This is why as written,  the rules are confusing, and the spell is useless.     

좀 이상하긴 함. 은신 규칙에 투명 상태를 넣었으니 여기엔 마법적으로 투명해지니 뭐니를 넣어야하지 않았을까

It's kind of weird, because they put invisibility condition in the hide rules, so I think they should put something like magically blahblah here.