If you're a regular runner you've probably already bought a GPS tracking device - perhaps a Forerunner (maybe a 305, 405 or the new 310XT) or some other device. You've probably also concluded that whatever software came with it is no good and looked for a replacement.
If you're using a PC then the only software that I came across that was worth having was SportTracks by ZoneFiveSoftware. It's technically free - but they ask, and I'd urge you to make, a donation. SportTracks is really very, very good. But it's PC only and whilst it does work inside software like Fusion or Parallels, it can be difficult to get working and when I was using it I ended up keeping a PC on my desk, next to my Mac.
There are rumours about a version of SportTracks for the Mac, but they seem to still be just that, rumours.
For Mac users, I'd always thought that the choice was more limited but there are at least two great options: Rubitrack and Ascent. Both of these are nearly perfect options to use instead of SportTracks not just whilst we're waiting for SportTracks to come out on the Mac, but for good.
I've written before about using Ascent so won't repeat any of that here. Rubitrack is very similar and it has, just, the edge for me. Trying to boil it down to the biggest differences, Ascent is slightly more technical in its capability - it has greater graphing and reviewing options - but Rubitrack, for me at least, has better presentation and sifting and sorting. Both of them auto-label your runs based on prior runs, but Rubitrack makes equivalent runs easier to find - allowing you to sort by location, by timetable and by distance with selections from the left hand menu bar. I also like the way Rubitrack can present the runs as icons - like the picture below.
Neither Ascent nor Rubitrack include one feature that I used a lot with SportTracks - the ability to tag runs with a piece of equipment and then keep a count of how far you'd run with that gear - for instance, you could note when you started using a particular pair of shoes and it would keep track of the mileage you'd got to, allowing you to figure out when to replace them (or at least to get ready to - given it's all about how far and hard you run I suppose).
Two very good choices then, with Rubitrack having the edge for me. The good news is that both are available as free trials allowing you to put a limited number of runs in without making a big commitment. Try them out and then pick the one that suits. And when SportTracks comes along for Mac, if it ever does, you may stay just where you are ...