I was lucky enough to get into one of the free classes the first week they opened and I'm so glad I did! The class itself is definitely a butt-kicker--I had to pause several times because I for sure felt my "barre3 shakes!"
Their method is to increase your heart rate with cardio and target specific muscle groups with a one-inch movement. So imagine holding a squat and then pulsing up and down but just an inch. One thing I really appreciated was that as soon as you walk into the studio the instructor asks if you're new to class and if you have any previous injuries. You warm up with a lot of aerobic movement, and then immediately get to work. I really liked the leg work we did with the barre3 ball, like leg raises with the ball under you or clenching the ball between your knees when doing standing work to get a deeper workout.
In the entrance there is a coat rack (key for WI winters) and cubbies to put your shoes and belonging. I am a student and brought a giant backpack and had no issues fitting it in the cubbies--which sometimes I do in the lockers at the UW rec centers.
Barre3 also has an online component, but you really can't beat the in-class experience. All in all, I'm really happy that I went, and I'm really happy that it's conveniently less than a mile away from my office. If you haven't gone yet, I encourage you to check it out!!