I use the paid version, wich I buy a year at a time since its cheap. there are some nice tools for graphing your power and progress there...and I like the paid maps better...but really because I can do all my data in one place, and have some decent analysis tools.
I can plan my workouts in advance and have it email me what I need to do for the day. i like that when i am traveling for work.
of course garmin connect is close but I so far cant track my weight automatically and it doesnt have the power analysis TP does.