I got the NYCB workout vol. 1 and 2 and they both are ok. After doing either of them, keep in mind I'm not that fit but am not a unhealthy person, I didn't feel any burn or soreness like when I do other things to exercise. Maybe you have to do them back to back.
I study modern dance and performance art, so this was a great way to practice intermediate ballet technique in about 30 minutes at home. Also the moving warm-up was effective! The core conditioning is good, as are the stretches. It's slow, so I usually do it double the rhythm.
I enjoy the workout, but it is very simple if you are already a dancer. Many of the exercises are taken straight out of any ballet class. If you already have NYBallet Workout 1, don't buy this one, they are almost identical. (I made the mistake of getting them both at the same time.)