I just got this today!! It totally kicked my butt... I set the level to intermediate, and decided to just leave the 30day goal thing how it was set ( next month I'll up it!!) I agree with most of the pros and cons so far. I realized too, that I had to wear the leg band high up on my thigh. Also, the type of material in my workout pants mattered a HUGE deal. Started with windpant material, ended with shorts and the strap on my skin.
The rollerblading was brutal for me, as was the running. Overall I like it!! I like the goals, I like the trophies. The sports drills are pretty cool.
Best part: Don't need the expensive balance board!!

I will definitely be joining the challenge!!