Love!!
I've been going to reformer classes for awhile now, and the class I took (Reformer + 1.5) took it to an interesting level. It wasn't crowded. The instructor was nice and encouraging. The music was great (e.g., Ja Rule, Eminem, Beyonce/Jay-Z, etc!). As far as the class itself - there was a good solid part where you were jumping...but laying on your back. This way, it took the benefits of jumping (cardio and legs) without the stress on the knees/joints. The other parts of the class also focused on the arms and core.
Overall, I felt like it was a twist to the typical reformer classes I've been taking. It was fun!
PS: They also have FREE demo classes. :D