I think the Live paywall to access these other paid services is bullshit. I really wish they were separate entities. I don't game that much online and the services that Live offers me now aren't worth my $40-60/year.
I completely disagree with that aspect of their setup.
That said, this is pretty awesome. This is something I wanted with the P90X videos did. If they have stat tracking and able to talk to Kinect to input info (weight, reps, etc ... ) that would be awesome.
I think this type of service is the correct vision for what MS wants these to become. The problem is that you need to pay first before you can pay for these.
It's like paying a $10 cover charge to get into a mall. Or paying for iTunes so you can buy music. The point being, if you are selling additional services for your console, don't have us pay yearly just to be able to shop for these services.
EDIT: How does Kinect monitor your heartrate?