I think the online is great, even at this early stage. If I owned the game, I could certainly get by on it; I only had a chance to try it for a couple hours, but I had a blast once I found a server with some decent players.
GT Life is "meh" and needs more Special Events, but it isn't a huge problem. All of the inconsistent, wacky decisions here and there are neither a surprise nor a hindrance to me, except for the inexcusably long waits and excessive button presses to accomplish simple tasks. However, while GT is hardly a bad game (it's a quite enjoyable drive), it really doesn't bring anything to the table that I can't find elsewhere.
I'll play Live for Speed for free online multiplayer, and pay for Xbox Live if I want to play with licensed cars in Forza 3. If I want licensed cars and realistic physics (FM3 doesn't offer that), I'll play Enthusia. If I want an immersive experience with my Logitech G25, again, there's LFS, with the best physics and FFB effects I've found. If I want to tune up and modify cars, Forza's there for me. For offroad/rally driving, I like FUEL more than anything else. The Top Gear Test Track was already available as a mod for PC sims before GT5 came out. Several of the games I own (eg. Enthusia, FUEL, PGR4) sate my desire for rain/snow driving, and GRID is fine for a time-changing race at the 24h of LeMans.
In the time it took GT5 to release, enough competitors and other games filled the void that there's really no need for it. It's impressive enough that I need all of those games to match the feature list of GT5, but as many of you are well aware, GT5 is more of a jack-of-all-trades than a master of any. If my only console was a PS3, sure I'd buy it, but especially as a 360 owner, GT5 is the alternative, rather than the trendsetter. And I'd need to borrow my sister's PS3 to play anyway.
I voted "Somewhat satisfied." I might get it and play in the future (I'll keep an eye on what updates bring), but for now there's no point.