I had an Edge 305, which was one of my favorite pieces of electronics. It had a design flaw that resulted in it being replaced twice, and when the third one died I waited until the 500 came out. I think the 500 is great. Here is the most in-depth reviews of it I've seen, and it's a bit out of date because Garmin recently upgraded the firmware to address some of the deficiencies noted in the reivew (like the lack of workouts). I recommend the 500.