I'm partial to CycliStats myself, but as the author, I'm 100% biased . It's been on the market for 3 years or so, and is (IMO) very good. You can download a free, fully functional 30-day trial version from the website.

As for Giga-Bike - they've only been on the market a few months. I downloaded their evaluation version, and was pretty p*ssed to see that they had copied some large sections of my program (the Options window, the way of describing terrain based on profile, etc.) I also don't understand how they can claim to be on version 5.9, when the software has just been released. I suspect they numbered it that way because CycliStats is on version 4.10

I've not evaluated Cross-Trak in a few years. As I recall it was OK (especially for cross-training), but a bit clunky to use.

All 3 products offer trial versions, so you can download each and try for a few weeks to see which one best suits your needs.