While the previous expansion was highly praised for it's size and variety Plus unfortunately adds a smattering of content that is largely underwhelming and even undermines some of the content added by Afterbirth.

The new enemies, items, and challenges extend the content a bit but far less than the previous expansion, and the victory lap and HUD features feel overdue but welcome. That's the good news. The bad news is the new characters add very little, the new difficulty for Greed Mode turns it into a chore, the new floor is little more than a reskin with bosses in every room, and the new boss fights are very underwhelming albeit each for different reasons. The dev tools are there but only really matter to the die hard community members.

All in all this is a pretty lacklustre addition to the game which takes more substance than it adds. It feels like lazy padding which has gone on to be shown up by the player made Antibirth expansion which wipes the floor with Plus with sheer creativity.

NOTE: This is a review of the DLC, NOT the game as a whole. I love Isaac Rebirth, see my review on it if you're curious as to why.
Afterbirth Plus is easily the worst DLC of them all. It barely adds anything at all and what's here is incredibly mediocre. Let's start with it's major additions.
The Void SUCKS. Not only is the entire floor big as all hell, it's really, REALLY easy. Imagine Basement 1, but they give you Tech X, Brimstone, and Polyphemus on the first floor, and you have The Void. You just steamroll everything in your path. Sure, you could somewhat say that about the main game, but that was much rarer to achieve. And don't even get me started on the glitchy nightmare that is Delirium. He's so glitchy and can telefrag you whenever he wants to. He's also way too damn fast. He's a fun fight, but he can be pretty annoying at times.
Greedier Mode is just harder Greed Mode. Not much else to say.
There are 2 new characters. Forgotten is fun, but Apollyon, while also fun, is way too similar to Isaac. You void bad items, just like you'd D6 bad items.
100 new items, which is fine. But there's a lot of items that are almost entirely worthless. Unique, but not good enough for another major DLC.
The 5 new challenges are AWFUL. The only one that's decent here is Pokeymans; the rest are terrible. Backasswards is just RNG, April's Fool isn't fun, Pong is pretty much just slow roll, and Ultra Hard is the worst challenge in the entire game.
Overall, AB+ just wasn't a good DLC. It's too miniscule in content, and the new stuff isn't all that great. Buy it for Repentance and nothing else.