Some random impressions after a few hours with the 360 version:
-Game comes on 2 discs. 2nd disc is multiplayer.
-There's a Uplay pass included, however you can play online without registering it. You will miss out on upgrades and extras though.
-Running and climbing is faster, more fluent and less frustrating.
-The new setting is great so far. Really atmospheric.
-Combat seems dumbed down, but this might just be because it's the beginning of the game.
-New finishing moves are visceral and very cool.
-Framerate is all over the place. Appears to be unlocked as well, meaning it will go anywhere from 60 FPS to low 20s depending on how much the engine has to render. This is really annoying and I'm pretty sure the other games in the series were locked to 30 FPS.
-Open world "jank" is still evident.
-Weird bugs like guards spawning directly in front of me causing me to fail a stealth mission and some weird stuttering when switching from cutscenes back to the action was slightly disappointing. Seems somewhat unpolished, but again this might just be unlucky open world "jank".
More to come...