URC 300 w/ RF
I have been using the URC 300 with the RF base station for a few months and I am happy with the purchase. I bought both for just over $100 from Amazon which is comparable to the cheapest IR Harmony remotes.
I agree with the above poster. Go with Harmony for ease of use with the web interface, but buy the URC if you want powerful macros, customization, control of more devices, and RF. The Harmony w/ RF is $300. It does take me 10-15 minutes to setup a new device by "manually" learning most of the commands. It would probably take a similar amount of time using the "automated" web programming for the Harmony.