This question was asked a few months ago and got some varied replies. DH wanted to do this but when we went in September, we went into the observation lounge and it actually looked really rubbish. You have to do training beforehand, after which you get 3 2 minute goes in the chamber. Unless you are an expert, when you are in the chamber the instructor is with you holding you so you don't really do much floating.
DH decided it wasn't for him but I think, like most things, it's down to personal opinion.