So I'll admit that I'm still rather early on in the game (I think) but I'm finding this to be an actual game where the gameplay is physical. This isn't a game you can rush through, so I'm imagining it will take me time to really dive into. The game records actual time spent doing physical activity, and after about 20 minutes, I can really feel it. I'm definitely getting a workout.
More importantly, it's fun. I want to be playing more. My physical limitations are what's limiting me, and that's fantastic. It means I'm driven to play more. And I love that.
As to the $80 price tag? It makes sense to me. This is some impressive tech that makes good use of the system. It's peripherals that are well designed.
If you think it can help you be more active and that's something you want? I'd say buy it. You're worth it.