at my hospital its like a standard delivery room but bigger, still has a bed and a little cot for the baby and all the resusitation/warming units for the baby etc. the lights could dim (but they could in all rooms) it had an en-suit bathroom with a shower and a toilet and no it was at all smelly or acoustic like a swimming pool!
Bit different from the above descriptions at my hospital. Very small room. No bed. The pool is shorter but much deeper than a bath with steps to get in. En suite bathroom but instead of a bed there was a sort of couchy-bean bag thing to encourage active birth if you want to get out of the pool.
No idea where MW & DH will put themselves as didn't appear to be any seats - hope they bring some in!