Just to add to the discussion here... I am currently trialling PC design software and iPad app from Demopad (http://www.demopad.com
). Is still in relative infancy but allows the iPad to control anything using Global Cache devices (like distrubted extenders). I am so far impressed with their PC designer... requires a lot of set up work (mainly flag based) but they're adding features all the time and are very open to feedback on new features. You can built a pretty smart looking UI. Currently hads 2-way IP comms with Creston/Lutron and I hear custom device 2-way feedback (232/IP) is on the way.
I liked the Pronto for what it did, and to be honest iPad is a little on big side for every day remote use (maybe that rumoured 7" iPad will help), but when you consider total price and overall abilities it is (IMO) a step forward over Pronto. Same app and software can also be used to design iphone/itouch interface which I am looking at next. I kind of see an ipad as a multi-room controller (cos of screen real estate) and itouch/iphone for single room use.