...since I'm hoping to get my mitts on a Garmin Edge 500...

I wrote this over a year ago so it probably needs an update, but is a good start: adrianspender.com

I vote for Strava as well. Although of them are good at comparing your performance on micro-segments and not your overall ride, though.

Motivation-wise Strava wins hands-down. The social features on Garmin Connect are incredibly basic still, whilst Strava's combination of segments, following, challenges and clubs has been a great motivator for me to get out more. The only danger is that you can end up pushing yourself more on every ride rather than just sometimes going out for pure fun/relaxation.

In terms of recording with an Edge, I'd say Connect still has slightly more detailed display of data. It is mostly there in Strava but you need more clicks to get to it. However the big wins for Strava I outlined in the blog post still hold - better and more interactive mapping, gradient etc. At least Connect has gone back to giving GMaps as an option and has moved to HTML5

I've logged (using my phone) my first ride on Strava, and I already love it. Being 189th out of 203 on one segment is a fine motivator in its own right. I have lots of excuses...

Segments are dangerous. I'm now addicted to trying to sprint up Ampfield hill (amongst others) to improve my standing, when I should be working on my overall ride times.