Bough it, tried it for 90 minutes last night. Only got a chance to try the multiplayer free roaming option, single player is for another day/week, just too busy.
Graphics: Outstanding, I was expecting frame rate issues because of the vastness of the graphics and the level of detail but no, it looks great and is smooth. I’ve heard there can be bugs though but in a sandbox game, it seems to come with the territory but so far, nothing I've seen. The vista’s are beautiful, at one point we explored the northern areas (and got mauled by Grizzly’s! LOL) and we walked towards a sunset and it was a mind blowing feeling, just beautiful.
What makes the graphic effects so fantastic is the animation though, with the horses animated extremely well, and with the game using what I think is called the "natural motion" animation system, which really adds to everything. Basically, it has a "location based" shooting mechanic, which has been done before but maybe not as well as in this game. So if you shoot a man from a horse, pending where you shoot him, etc, it gives the impression the animation isn't canned, with him/her falling off a horse in multiple different ways (some providing LOL moments). This excellent effect also works when shooting someone on foot (ie: shoot him in the leg, he'll be crawling). Again, it's been done before, but there's something about this game that seems to elevate the animation to the next level and certainly makes it feel fresh.
So that’s about it. We messed around, there were AI people that attacked us, sort of Gears of War 2's Horde mode, was very cool. I heard they had lots of multiplayer issues last night and I did have a connection issue at the beginning (and a problem trying to enter one of the bonus codes that came with the special edition of the game) but all worked ok. I know that’s disappointing but the presales on this thing are off the charts so I’m not surprised they had issues and I’m guessing they’ll be resolved shortly, once they figure out how many servers to add, etc.
As mentioned, didn’t try the single player game, so can’t comment on it at all, but so far, huge thumbs up on the game, glad I picked it up.