I have just moved from Endomondo, where even though I may run a 5k run, if one of my 1k splits is a personal best, it will record it. I rarely go out to do a 1k run, but it would be nice to see when I have reached a 1k personal best while doing a 5k run for example, or push myself to do a 7k run, because I feel I can, but if the first, middle, or latter 5k is a personal best, it should calculate it.
This is the biggest feature that I have missed from Endomondo, and is sort of a deal killer. (I left them for other reasons). I shouldn't have to stop at 5k, press stop, hold reset, and then start again to get a run recorded as a personal best if I want to run further.