I have been coming here about once a week for 2 years or so. I love Hot Yoga. I go to yoga at my gym once a week or so during lunch hour, and it really does not compare.
I buy the class cards. If you sign up for their newsletter, Isabel (owner) sends a blast out every so often about a sale on the class cards. Its usually a pretty big savings, so I re-buy then. They come in 10 or 20. There is unlimited class packages as well for the diehard yogis.
Tula is very busy. The right after work classes are packed. If this is a problem, you may want to look for a different studio. I don't mind as long as everyone is accommodating. They have opened another (not hot?) studio a few floors up which may help.
Bring a Lock and use a locker, as another Yelper mentioned, the bags everywhere in the class is super annoying.
After coming for so long I have figured out which teachers are good and which to avoid. Isabel, Davian and Grace are all great. The Christine's are not bad. It REALLY depends on the style you like and which teaching style you prefer.
Its a good studio. Try Hot Hatha first, its the easiest to begin with.