Delivered in an eleventh-hour patch, online multiplayer is not wholly bad. There are neat racing ideas, like shuffle races that dole out cars semi-randomly and a free run phase with a 'track day' feel before the race itself (not that anyone's using that, currently). The "community" presentation within GT Mode, focusing on your friends' profiles, is great; you can gift cars and items, chat on messageboards and follow each other's progress here, as well as start private races. Racing is highly customisable and it will suit a consenting group of friends very well.
As a public game, though, GT5 needs a lot of work. There's no matchmaking at all, so you have to browse a list of rooms and pick one, or enter an alphanumeric code, as if you're playing a PC game and it's 1999. The netcode is unstable; after a long pause I started one race alone on the grid, with the rest of the field halfway around the track already.
The game's lack of a car classification system (less of an issue in the offline GT Mode than it used to be) means an unruly free-for-all that will soon stamp out the use of anything other than thousand-horse monsters. There's no persistence or reward for participating in multiplayer: no experience, no money, no ranking, not even points carried over consecutive races.