If you really like the RCU810 you don't have to go and spend over a hundred bucks on an MX500, all you need to do is buy a $15 JP1 cable.
The problem with the RCU810 is just that it has limited "learning" memory. It has a huge chunk of memory that is not accessible to the normal user, but is accessible to the JP1 user. You can use this memory to create upgrades for all of your devices, plus you can use "key moves" which is a feature common to One For All and Radio Shack remotes, but was removed from the RCU810's menu system. However, the functionality is still in the remote, so with JP1 you can use it.
Rob
http://www.hifi-remote.com