The personal heart monitoring means you can go at your own pace more effectively. Especially when starting out, it doesn't matter what everyone else is doing, or even what the coach is saying - you can look at your own data and decide if you should push more or not. I would say it's ideal for people who aren't traditional gym folks, like myself, who aren't motivated by competition with others but more personal goals.
It's a one-hour total body guided workout. It's highly effective and fast. I always feel like I've had a good workout after and can confirm that by looking at my heart rate graph and calories burned. Also, the energy in the studio is super fun!!