Originally Posted by Chaco

I've been very happy with the 500. It appears to be MUCH more reliable than many other devices, including other Garmins, on calorie counts. Mine generally comes in at around 25 calories per mile for a 30 mile ride with 2500 feet of climbing and an average HR of 145 [my max is 170]. Other devices typically report up to twice that amount, giving you a very unrealistic view of how much exercise you've done.

I've never had a problem with mileage, or for that matter, any other measurement, except for elevation. My Garmin tends to report it about 100 feet too low, but that's a relatively small problem for me.

I particularly like the ability to download the data and review it after the ride. It really helps you see if you're improving on common sections of terrain.

I also like the ability to have 3 different customizable display screens.