I'm like NY. I don't use my phone for anything except phone/text when I'm riding, for all of the reasons she stated. I have a Garmin 1000, which could do all of the things you are talking about, but I only use it for distance, cadence, speed, and average, as well as downloading routes from Ride with GPS. I stopped using my HR monitor about 8 years ago. It never worked right, and I was just focusing on that. I've been exercising for 35 years; I know when I am working hard and when I need to back off, so RPE works fine for me. As far as calories burned, my take is that it's all wildly inaccurate, especially for someone who is five foot almost one and weighs between 105 and 109. I guess I sort of subscribe to RocknRoll Girl's theory.