ATTQOTD: I use the iSmoothRun app on my iPhone. I like: that I can set up any intervals I want, set up and save specific workouts, the sound and tone of the voice-over commands, that it syncs with my music, that it records a ton of data I want (weather conditions, maps, elevation, avg pace, net pace, shoe mileage, fastest song, fastest mile, etc.), that I can program alerts for nutrition/distance/pace/time, and that it exports to Runkeeper. I dislike nothing, which is why I've been using it for 6+ years!