Nuffield Health

Never gets too busy or frantic and there's usually one or more of the machines that you're after free. The staff are friendly and unpushy and the people who go there are nice. I've never been a member of another gym so don't have much to compare against, but I'd happily recommend this little fella.

I have been a member of this gym for quite a while, for me it's really convenient as it's so close to where I live. However, the gym has some real problems, the first is its website is very rarely updated, so their class schedule online is never accurate, so beware of showing up for classes that aren't happening. Having said that, the classes are really good and are included in the price of your membership.
I joined this gym specifically for the pool (although there were nicer/cheaper gyms in the area), however, it is so crowded during the day that you end up swimming in a single lane with five other people all swimming at different speeds! The changing rooms are really dirty, the majority of the showers in the lower changing rooms do not work and unfortunately some of the lockers in the upper changing room are warped because of a past flood so they often cannot be opened with ease, I've spent a good twenty minutes trying to get my stuff out. Also the gym is located below a curry house and so often smells strongly of curry.
The staff on the whole are friendly, but beware of the overzealous staff on the gym floor who want to sell you personal training sessions. Their constant interruptions to your gym routine can get really annoying.