I'm an old-school shooter fan so I wasn't sure if this era of shooter would be good. I was pleasantly surprised and had a LOT of fun with it. Enough to warrant playing New Game + for once.
The Good:
Gorgeous. The game is just gorgeous.
No bullet sponges (other then bosses).
The Narrative and how it integrates into the level design. This I think is the best part of the game. Old school FPSes had platforms and doors popping out of nowhere and we just all accepted the overly gamey aspects as par for the course. This game uses the narrative (and other character attributes) to explain away these things so you never get pulled out of immersion. Really brilliant.
The So-So:
A little short. It took me 6 hours to play through the first time. However, at current prices it's WELL worth the money. For instance, Singularity took around the same amount of time and cost quite a bit more when not on sale.
Regenerative health. Honestly, I didn't mind this game design choice here at all. It fits really well with the overall experience, but some people truly hate regen health so I thought I'd mention it.
Quick-time events. Again, the way they're done it's actually a good design choice for the experience, but some people truly hate them, even when done right (which they are here).
The Bad:
So this one is a bit controversial, but I thought the actual Quick-draw Duels sucked. It's unfortunate, because this is actually such a core part of the game that they even made a second mode of just Duels.
During the campaign you only have a half dozen or so of these so it isn't enough to detract from that experience, but they are the places where I kept dying.
I just didn't enjoy them, but others may.
TL;DR - Buy it. You won't regret doing so.