As a huge fan of the Assassin's Creed franchise, this game was really disappointing.
The weird thing about AC Unity is that it's an excellent game ruined by horrible business decisions.
Finally, stealth is fixed: there's a crouch button, combat is harder, and there are more options for stealth. Parkour is easier and more fluid. Combat is the best it's been since AC2, at least. Customization is finally here, and you can completely customize your outfit based on your playstyle. Different weapons with different stats are back for the first time since the Ezio trilogy. Paris is beautiful, massive, and feels alive with all the enterable interiors and all the people in the streets, and the graphics are the best I've ever seen in a video game (including Crysis 3, Dragon Age Inquisition, Far Cry 3, GTA V, etc).
These things all sound great, right? They are. Which is why it's so sad that the game got ruined.
Horrible optimization means almost unplayably awful performance. On both low and max settings I usually get the same FPS, and I've never gotten a constant 60 (for reference, I have an i7-3770k, a GTX 680 SC, and 16GB of RAM).
Beyond performance in gameplay, performance in cutscenes is usually around 15 FPS.
A lot of the chests you find in the world require you to log in to a separate companion app on your phone to unlock them, which is completely immersion breaking and really sucks.
For some reason, everyone in Paris speaks with a British accent (which is more annoying than it sounds).
You're required to go through Uplay, a separate client, to play the game.
The co-op often doesn't work because the game can't connect to Uplay.
The second thing that shows up when you pause the game, right below "resume," is an option to go pay real money for in game stuff. This ♥♥♥♥ing sucks for a $60 game when micotransactions up to $100 are shoved in your face.
The best armor and weapons in the game are locked behind either a real-money paywall or a requirement to use some stupid external companion app.
The mini-map is stuffed with so many options that it's almost impossible to find anything useful.
Overall, this game is incredibly disappointing, not only because it follows the amazing Black Flag, but also because it could have been the best AC game ever if it wasn't completely ruined by awful business decisions.
Don't buy this game.