I have had Mac's around me in the family since they were invented, and continued to use both, but I have been mainly using Windoze XP and 7 for the last 15 years. I just got a new Macbook Pro (Mavericks) though and caught up with the rest of the family!
I have GPS-Results running both in Native Mac and Windows XP in VMware. The windows version has extra features needed for analysing records and vetting tracks for errors, but for basic normal use the Mac version does all you need, especially if you are completely comfortable with MacOS.
VMware and XP actually take up surprisingly little hard drive space and it is very easy to install and run. No partitioning or other technical stuff required. So far I love it! I can flick from one to the other with a swipe of the fingers.
GPSAR-Pro runs exactly the same in both (Java) so if you can work out the quirky interface it is great!
RealSpeed only runs in Windows and works in VMware perfectly well, in fact both GPS-Results and RealSpeed seem to work faster in the Mac under emulation than they ever did in my older Lenovo R61 Windows XP system!
It's a shame that RealSpeed has not had any recent development because it does a lot of things very elegantly. For editing tracks, file format conversions and for some types of track troubleshooting analysis, it's usually the one I go to.
Overall, I would say the Windows version of GPS-Results is the most complete package right now and well worth the price, but they all have their advantages and all do the job well.