Some of the major downfalls, IMO, is that the M1/EZ8 can't talk to the W800RF directly, and the lack of support for IR. I know Elk is pretty busy, and they are looking into some solutions, but those 2 items alone are major showstoppers if you are interested in the HA aspect. If it did that, it could replace many HA setups instantly. I plan on keeping my Ocelot/SCU16 in service, and am looking into using ASCII messages to trigger IR events, but this means I need to get another serial port expander.
As for the W800RF, I am thinking about writing a small application, which understands the W800RF protocol, and send a messages the M1/EZ8 whenever there is something going on. I just have to figure out if I should use ASCII messages or what, since I don't want to run into any potential memory limitations by using so many ASCII messages.