I agree with Natasha. I actually just did this workout tonight and I had forgotten how challenging it was. I figured that, with 2 Mesos of STS under my belt, this would not be that challenging. I was wrong. In fact, I was not as good at it as I was when I was doing it more regularly. When I did the stretch, I could already feel what usually ends up being DOMS within a day or two. The upper body portion is low weight and high rep, no biggie. I think it's the lower body portion that is worth its weight in gold. A lot of the work is what you might call "leg conditioning drills", standing, so we're talking leg lifts, outer thigh lifts, lots of pulsing, and some traditional barre poses, which are effective and really get in the inner thighs and the calves.
What I do find unique are the one legged leg bends where you are pulsing down on the standing leg while hold the other leg up, that downward motion is harder than it looks, and it burns the standing leg right in the glutes, giving a nice burn. If you don't have a strong lower back, I would recommend you ease into it, as all that standing leg work can be hard on it, but I think it gets less annoying with time.
I've never done any other barre workouts, so I cannot compare it to those. What I can say is that it is an effective lower body workout, and I've done plenty of those.
I would agree with Natasha that this is a great leg slimming workout, but it's not stressful on the joints. I get tired of doing lunges and squats with a lot of weight, and I found this a welcome reprieve from those types of lower body workouts.
Come back and tell us how you like it when you have a chance to do the workout!
Eva