The best gyms are in the hotels. However they are pricey and they aren't like gyms in the USA or in Europe. Sheraton by far has the best gym in Doha, the best beach.. ok the pool kinda sucks but luckily the whole place is going under remodel in a few months!

As far as Gold's yes it's ugly and I don't know if they are really Gold's Gym licenced or just stole everything
All I know is that nothing is like Equinox, Sports Club or 24 Hour Fitness here.!