TLDR: Solid enjoyable story but very lacklustre gameplay. But it is worth your time.
About the gameplay:
The RPG stats and perks very loosely effect gameplay to the point where it's possible to never upgrade them and still work through the game.
The weapons felt poorly balanced, heavy weapons have the highest dps outright and the skill in-game don't effect damage at all enough to merit using anything else unless you want to challenge yourself as they gave each weapon type bonus effect chances. in contrast, fallout's skills all boost gun damage so you're able to switch up the game play from heavy tank to stealthly assassin.
The big problem, though you might not see it as much, is that dialogue based skills have WAY too much effect in-game as almost all NPC's have player beneficial responses for each of the three skills. It also overly effects stealth as when your "disguise" wears off or you're spotted, you can also talk your way out of the situation (atleast twice) while also having you "disguise" fully replenished which, in my opinion, heavily robs the player of a stealth focused playthrough as it would most hang on have good speech skills more than building any real stealth skill.
It would have been a lot more enjoyable if they didn't focus on trying to ride on the success of fallout:NV and made a more generic fps similar to Bioshock.