I've mentioned this a few times in other yoga posts, sorry if I'm just repeating myself.
I've been doing bikram yoga for a year. I haven't been to the gym that whole time, I do the yoga almost everyday. It is time consuming, 90 minute class, but my body has never looked so good. It totally changed my whole physique. I am going to start doing some cardio though because I just miss it!! I have also been able to maintain my weight without trying too hard, but I do watch what I eat.