I won one with work once. Ferrari experience at Rockingham. I wasn't expecting much as it says 4-5 laps, but to be honest I really enojyed it. You feel like you get a long time, and the drivers aren't nursing the car, they tell you to gun it if they are confident in your ability. I got to choose between F1 paddle shift, or a stick shift Ferrari 360. Sounded amazing, goes like stink and really highlighted just how well these things handle. The frustrating thing is, just as your getting to the end of your 4 laps, you're starting to get confident, carrying more speed, braking later, hitting the gas earlier (even managed to get a bit of a power slide going on the final hairpin
).
At the end of it all, you feel pretty exhausted, even though it is only a handful of laps, but you are working hard, concentrating and trying to just enjoy it!
The really funny thing was at the end of it, they started offering discounted lamborghini and parsche experiences..... my mates had to drag me away from the Gallardo!!!!
To sum it up, they are good fun if you relish the experience of driving a supercar and your happy to take that away. But it is a bit short and you do feel you want a bit more. If you can budget a palmer motorsport day (about £600 I think) they are meant to be fantastic ( a few colleagues have done it) and you're driving all sorts of cars through a whole day.
Hope that helps.