I bought this game specifically to learn my way around Donnington Park. Having looked at the glossier Tourist Trophy I decided on this, purely because I'd played GT4 (Tourist Trophy is GT4 with bikes rather than cars) until I was bored of it, and wanted something different.
The balance and physics of the bikes is amazing. I'm a real biker, and I think this is as close as you can get to the riding experience without leaving your armchair. I've only been lucky enough to ride a few of the bikes included in the game in real life, but their character traits are all there, from the R6 lacking midrange to the accuracy of the CBR6RR.
This is not really an arcade game, and it requires patience to gain any level of skill on the bikes. They're not forgiving - but then, neither are real motorbikes.
All in all, a smashing game, I'd give it 5 stars if the graphics were as good as Tourist Trophy - but don't let this put you off. Take a look at the downloadable intro movie, this is exactly the way the replays look when in the game.