I've been to the Sherwood Forest one. Its good fun, but on the day we went it was pretty busy, so we had to wait at the start of each stage for about 20 mins. It would probably be OK if you went on a non school holiday weekday. You get instruction and a practice obstacle to show you how all the safety gear works, then you are more or less left to it. Bear in mind that all stages end in a 'death slide' and after the weather we've had the landing areas will be very, very muddy, so definately go in old clothes.