Did you like Assassin's Creed 2? No matter the answer, you will love Brotherhood. But especially if you answered yes.
Also, as a PC gamer I very much appreciated the time and effort that Ubisoft put into my playing experience. Personally, I play with an XBOX 360 controller for games such as this, but I do have friends who use the keyboard and mouse and state that the game operated beautifully. Aside from controls, animations and graphics were also beautiful. The high resolution textures was a nice upgrade from the console version.
Another area where the developer took time was in the insurance of the fact that the game ran well on all machines at launch. Unlike games that release with bugs and issues with certain cards or hardware configurations, AC Brotherhood ran like a beauty straight out of the gates.
Why didn't this game get a 10 from me? A few bugs in the engine that I feel should have been worked out by now. For instance, occasionally you feels as though the character performs an action similar to what you wanted, but not exactly as you entered into the controls and something that you obviously wouldn't want to do. For example, several times I found Ezio running towards the corner of a building and jumping rather than jumping straight from the ledge I was standing at.
Aside from that? I recommend that you play the second Assassin's Creed game before this one as you literally resume within the same cutscene. That concludes my somewhat hasty review of AC Brotherood.