Barre Code provides an excellent work out. In an hour you work your entire body and core. Fast, upbeat music and the instructor's motivation fills the room to keep you on track.
It's a bit intimidating at first when you aren't familiar with the exercises, but the instructors help you out and correct your form.
Don't compete or compare yourself with anyone else but yourself. You'll have a great time and feel really good (but sore) after.
The only drawback is the price...it's a tad pricey :/