Picked up the game on PC and PS4. Gotta say that after reading all the negative reviews I was ready to cancel my pre-order. The major issue I've had has been the framerate, which has since been patched up on the PS4, and soon for the PC. Overall I've found the FPS to be more consistent on the PS4 vs. PC (and I'm running a 770 GTX) though the PS4 doesn't get any higher than 30fps. PC is average of 42fps but bounces between 20-60, which means when there's chop, it's a hell of a lot more noticeable.
Visually, the game is stunning, if not a tad repetitive in some instances. I mean really, one grimy back alley is the same as the next. Even on the PS4, the game is a showpiece, though why they decided on a couple pre-rendered cutscenes is beyond me. They actually look worse than the ingame engine.
There's been a lot of griping about how closed the game is, and I can see how expectations of a sprawling city/sandbox might cloud expectations. The game is linear, albeit you can take on a multitude of jobs in any order you desire. There's enough territory IMHO to not feel like you're boxed in. I think Eidos Montreal did a much better job of giving the illusion of freedom than DE:HR did. The story isn't exactly groundbreaking, but it is what it is.
The most important aspect of the game, the stealth, was fairly well done outside of some weird AI issues in spaces.
I think like so many other games lately, Thief is polarizing. Fans of the original will balk at how this game totally missed the mark of greatness, but let's be honest - the old PC games weren't without their faults. Either way, don't let the reviews skew your decision to pick up this game, especially on PS4 (cause they need more games). Just realize it's not going to be a seminal stealth/combat experience like Dishonored. Thief is a much less ambitious of a game. If you're a fan of obsessively looting items (see Skyrim) and sneaking about in the dark, definitely check it out.