Yep, I've got it.
First off, when it's going it looks fantastic, the external car graphics are amazing. Tracks look brilliant too. Handling is superb. On the hardest settings it's hard, I've actually come one step back and I've turned the gearing from 'gears with clutch' to just manual gears because I was finding that too hard.
Bad points then. It's a bit buggy to say the least. The sound will sometimes just not change for about ten seconds so no matter what the car is doing, all you'll hear is this monotone hum. Sometimes the track will disappear for a couple of seconds too. Some of the menu items don't appear until you've selected them. It's MASSIVE, two disks, one of which you have to preload onto the hard drive and even then, loading times are long. When the car hits something, the whole bonnet instantly turns into this completely broken peice of metal, quite off putting. Car interior graphics are very poor.
And I don;t like the way you're forced down a rigid progression path unlike Forza 2 where you could pick and choose which race you did next and could also pick which upgrades you wanted to apply. You can select which upgrades you want with forza 3, but it's not as obvious or as simple, just a small point.
That said, it's an excellent driving game and I'd still say get it, I assume they'll send out updates for the bugs shortly.