Fantastic. Just the right mix of a lot of fun and a little bit of unpleasant! There a very friendly and welcoming atmosphere, but once it's go time it's all business - there's zero wasted time. The instructors are really helpful, attentive and good at coaching form, and helping/allowing participants to modify intensity as they need. An hour FLIES by and I walked out with a big grin on my face having had a great time.