I haven't been to many hot yoga studios, but I've a few great classes here - most are about 75 minutes, but it goes pretty quickly. It's broken up into several parts (I'm not too sure of the term!), but it's fun. The instructor moves the class along...and helps cool the room off by opening and closing the door when the room becomes too warm. So! If you don't want it super hot, get a spot near the back doors.
The only thing that I am not too keen on (and I'm not sure if this is just how it is/should be) is that the movements/transitions sometimes feel a little rush. Besides that though, it's a great experience. You leave feeling accomplished and refreshed.
Also - if you don't have a mat or a mat towel, it can be rented there for I think $2. I was unaware of the mat towel the first time I went, and they let me use one for free! How nice and welcoming, right?