i don't have much respect for classes at the gym. the people doing those classes don't want to be there, they hate it and the people that go aren't serious since the classes are 'free' in the membership
for example if i am going to do yoga i will go to a legit yoga studio. there better be fit hippies when i walk in and electric cars in the parking lot, not a bunch of old farts
having said that why not do the free classes if you want. you might meet some cool chicks