I use I Cardio and like it as it has several options for activities as well as storing data online. I have a minor heart condition and use it mostly for spin class as I can look back over workouts and see how my numbers are going. I use the Mio Fuze and find it very good I cannot speak for accuracy but i think I at least get the trend of what is going on. As far a calories burned I suspect that does relate to heart rate and is at best an estimate. Map MY Ride also intefaces with the Mio Fuze