I looked into them while enduring a string of storms this winter that kept me off my bike. They received enthusiastic comments on the Video Fitness forum. I don't know if anyone actually posted a review. I asked a competitive cyclist & coach about them & he wasn't a fan. He's one of Johnny G's trainers - he trains Spinning instructors so his comments weren't rooted in a dislike of indoor cycling.
They are pretty pricey. From the VF comments, it looked like they'd most appeal to experienced cyclists or at least hard core spinners. Hopefully Nancy C is going to comment, I think she has some of the tapes.