My mum goes and I got to go with her for free for 3 days last week. i have to say that I LOVED it. It was a really good workout for the whole body, took only 30 mins and I felt great for ages after it. It was brilliant and you dont feel self conscious at all, there are women of all ages, shapes and sizes there and the staff are really supportive.
I would have signed up there and then if I had the time to go but unfortunately my nearest one if 30 mins away. Once me and my OH move I will be getting a membership there straight away.
I think you can actually phone up and get shown around and introduced before you sign up. Maybe worth doing that at your local one to see it for yourself beforehand.