I bought this game very close to the release date among several other game. I tried this game at that time but I'd rather to play the other first because it looked more entertain at fist. After beating all of them, I decided to give a try to Unity. Well, after 4 hours straight in I couldn't stop playing it. I was so hooked to the game that I finished in 2 days (single player).
Even though, the story is not top notch comparing with the previous Assassin Creeds, this one is getting better though the end.
Paris is so well designed and drawn. Graphics in general is well (not totally impressive, I think because the crowed of people you will find the game make difficult to even current console cycle to handle),
I tried the Co-op and I think it is great. My recommendation to move forward faster in single player is to try the highest level of Co-op missions many times in order to get "coins" and "experience". With this you can get the necessary skills, equipment and weapons to go over the sequences easier. If you don't that you will spend a loootttttt of time trying to go over the missions.
The Cons are: a) I played all the assassin creed, so the basic same formula repeats over and over again, and b) The story, even is not bad, nor it is the best addition.
In general, it is a most play because at some point in the future (I think), every single assassin creed game will build up a complete history making each installment necessary to understand the overall.
Thanks for reading.