Aside from the fact that they cost more than what I'd want to spend, my concern is that they are priced too high to make major inroads into any large market. We've seen lots of different platforms come and go - some into the surplus market, others have just disappeared - because they were not able to hit some sort of critical mass. The Audrey above is one example. I understand that these new tablets are more powerful machines, but they aren't exactly cutting edge hardware either.
If these (the new tablet formfactor, not necessarily these specific machines) don't sell well, do we expect them to be around in another year? Will Microsoft move on to some newer platform? They've promoted several recently that haven't really gone too far - or haven't been nearly as revolutionary as they expected (the features have merged into other machines - machines much closer to normal PCs - or disappeared).
The high end PDA market seems to be slowing pretty dramatically. Dell has announced that there won't be any immediate successor to the X51v. HP/Compaq is apparently dropping its high-end line. Granted, these new machines should be more powerful than the PDAs, but they are significantly more expensive. If I'm primarily going to use the device to control my home, a low end PDA with connectivity (wireless/bluetooth) would be much more cost effective. Yes, a larger screen would be nice but is it really worth spending that much more to have bigger/more buttons to turn on lights, browse media, etc?
I understand points about professional installer/high end markets. But will you depend on this technology to provide your front end when you don't know whether it will be around next year? Will the professional installers be buying enough of them to justify their manufacture? What will you do when your chosen front end hardware disappears?
Anyway, I actually like this new form factor and hope it succeeds. I'd like to pick up one up myself. But I have my doubts about whether they will succeed, though. If they fizzle away without making significant inroads into any market, I won't expect to pick one up on the surplus market either. I think the days when companies made way too many devices they couldn't sell (see Audrey, above) are gone. Production seems to be held much closer to immediate demand to prevent excess inventories.