Actually I like the very fact that it is paid. Supporting the developer, and some sort of accountability.

Also, after trying connect, liftoff, jerboa (all perfectly good apps), etc I find that sync is most smooth and customizable.

I am a bit surprised about the diversity of opinions. For me, well organized muscle movement, both cardio and weightlifting, is quite enjoyable simply physiologically. Plus other things like resting the mind, enjoying the scenere, etc.