I have some things to say about AC:
1) On my new system, using a single 8800 GTS KO 512MB (G92) GA and a Core 2 Quad 6600 (no OCing on anything) the game is fantastic. I don't even have to close all my apps to run it, it is that easy with the new system. Graphics are fantastic, I have everything pumped up to max on a 1600 X 1200 resolution. I don't have frame rate specs yet but will get those soon.
2) The game engine is superb - when I am on a horse, for example, and I go into gallop mode, using my Trackman wheel I am able to 'steer' the horse without any pauses / glitches, and directional movement is always as fast as I input it.
3) The movement engine is a bit lacking, but this is partially due to the fact that it is more set up (using default settings) for a console game rather than a PC game, so that I can live with.
4) I have barely scratched the surface, in fact I am on my way to Acre right now to meet with the leader or whatever there, so you can tell I am early into the game - one thing that irks me a bit is that I missed so many of the side quests in the first 'assignment' - I have to go back and finish those sometime....
5) I hate the fact that I cannot just exit out of the game at any time I want to - I have to traverse a set of menus in order to quit, and that is, frankly, a big PITA for me.
My thoughts - IMNSHO :P