I bought this and Wahoo Fitness's Bluetooth heart rate monitor 'Blue HR'. Together they allow me to collect all the data I want when cycling and running. The Wahoo app is really well designed and can upload a completed session to loads of fitness apps. I have just opted for Strava and Dropbox. Dropbox can receive about 8 different file types, I have settled for GPX, CSV and Wahoo's own file format. The quality of the hardware is comparable to my backup Sunnto T3c. To finish it all off the iPhone lives in a Topeak Ride Case with stem cap mount.