Looks like the 605 has a lot of the functions minus cadence and HR. I never liked cadence on my Cateye, so much I didn't put the censor on my new bike! I have a Polar. DH will want these features so the 500 is likely better for him.

The local mountain bikers share gpx files, does that only show the elevation? How about the coordinates of the trail? I am a gadget dunce but I did upload some custom POIs to my Garmin Nuvi. I was hoping these files they share were like that?