I recently completed this game after getting it through Humble Monthly and I've plugged quite a few hours into it.
TLDR;/Short review: Overall, Quantum break is a fun game, it has quite a few flaws but the gameplay is really fun and the combat awesome. Would recommend getting it over a sale.
Long Review : So the combat in this game is the big seller for me, the time abilities are fun and can be used in a multitude of ways while fighting, from jumping from cover to cover while taking potshots at your enemies to a Rambo-esque run and gun fighting style. Combat is pretty fast-paced which keeps it challenging and fun. It is also pretty much balanced well enough to allow for varied fighting and play styles, which is always a big bonus for those who enjoy player agency in combat.
The story is pretty interesting, and although it is not great or something that unique or special, it is definitely good enough to keep me engaged throughout the gameplay and story. The sheer multitude of texts, emails, reports, notes, etc that you can find are quite nice features, although I did find myself skipping or speedreading through a whole bunch of them as there was just such a sheer amount of text to go through and read into that it can and does become a little bit tedious at times, which is quite a shame as they had some really interesting information in them most of the time, unfortunatley it was just so much reading that it became hassle to do.
I found the upgrade system to be slightly redundant, even though it does add some nice things to your abilities you can just as easily get through the game without looking for the chronon sources (which you need to collect in order to upgrade) and upgrading your abilites at all. They just don't really add all that much to the overall gameplay.
I must say that I did really enjoy the live action "cutscenes", they are a fun gimmick that makes the story that much more enjoyable although I know many I know who've played Quantum Break did find them a bit long.
The save points in this game can be pretty terrible at times, and you will be finding yourself fighting in the same areas over and over and watching the same cutscenes again and again, unless of course you're a glitch god who never dies of course.
The camera can also sometimes be a problem as it shifts to look at certain things during a fight and that can get in the way of the actual combat.
The game also requires the player to do a lot of climbing and jumping but the "parkour" system (for want of a better word) is a little bit finnicky and you'll occassionally fall off objects when you probably shouldn't and you can't climb some boxes that come up to your knee. It's not too game breaking however.
As I've said in the short review, this game is really fun, it has some issues but overall is a great game.
If I had to give it a rating I'd say a solid 7/10