The Harmony can learn commands as well as an MX-500, maybe even better. With the Harmony you can learn commands in "raw" mode which can be an advantage with some screwy commands that other remotes have problems with.

I think you'll find it is also more customizeable than your MX-500. The activities are very flexible in their setup, and a lot more powerful than a simple "macro". IMO you would need to look at an MX-800 or above as an equivalent to any Harmony.

I wouldn't touch a Kameleon. They aren't in the same league as Harmony or URC.