I did a 6 supercar day a few years back, Lambo, Ferrari, R8, Porsche 911, Aston and a GTR and it was about £400, 4-5 laps in each but it was literally straight line and one corner and you never really got the chance to open them up too much so it was decent but not spectacular. You got like 3 gears worth of power and thats it, nice to sit in that sort of car and drive it but very restricted.
However I won an 6x car SuperCar experience thru work and AMD to drive supercars thru the Cotswolds via
http://www.dreamcarevents.com/ (who I have no association with) and that was epic.
Usual overview, dont drive like a total nob, its your life, your license sort of stuff and give you the keys.
Ferrari 458, GTR, Porsche 911, Lambo LP570, R8 and a Bentley GTC
As an experience it was perfect, open roads, there was scope for opening the car up etc. There was an acceptance speeding was going to happen but scope to use your own sense. Anything silly would able to be tracked by them. Seem to think the cost was £1500+ per person tho so its not cheap and unless your were 25+ it was a total no go in anything like the above.
The highlight being driving through Bourton on the Water, which is a pretty civilised tourist town in the Cotswolds in the V10 lambo shouting "Oi Oi ladies" at the talent. Childish but had to be done.
Id not bother with any supercar experience these days bar something like the above or a Palmer Sports day which ive never heard anything other than rave reviews about but I think they are fairly heavy money.
You gets what you pay for!