Great circuit classes, that are different each time. So you don't get bored. Also there is three a week, so its easy to make it to one. Pretty good value as well. As you can pay per class (£10) or you can buy a 'monthly membership' card. Which means that for like £50 you can go to as many of the classes you want each month. Bargain, and certainly cheaper than David Lloyd. Would recommend.
They also do personal training out of a private gym!