Sounds like a fun app but the $15 a month fee to continue to use it is off putting. One of the main reasons I got my HMD was the exercise options and I didn't fancy being tied down to a £20-60 per month contract... Is there not an option to buy the app and that's it?
Well, there is the $120/year option, which is a good deal cheaper overall. The monthly option is more for people who haven't decided to commit to a full year yet, or I guess those who only plan on using it for a limited portion of the year.
Originally, VirZoom sold whole bikes (with the sensors and game controls built in) and there was no license fee... but IIRC, the base price of those was $400, so it's more like the usage fee was just included up-front. With the new sensor kits only costing $100, the monthly/yearly fee is necessary to fund further software development.
But I understand the reluctance towards any kind of monthly/yearly fee. It's comparable to a gym membership or any other kind of fitness class, but a lot of people aren't really keen on paying for those, either.