There's no question that the DUALphone is a handy little gadget. It combines the convenience of a cordless phone with the ability to choose between using Skype and PSTN-based calling. And the fact that it stays clear of the 2.4GHz band is a very nice plus.
However, the DUALphone isn't the only way to make and receive Skype and PSTN calls without being tied to your computer. Adapters such as the Actiontec Internet Phone Wizard with Skype [reviewed here] and other similar products can be had for $40 - $60, and there are plenty of cordless phones for as little as $20.
These lash-ups won't provide the Skype presence info at the phone handset, and require you establish speed-dial numbers for each of your Skype contacts that you want to call. But they'll let you get away cheaper than the $140 it'll cost you for the DUALphone - especially if you already have the cordless phone.
Still, if the phone's popularity outside the U.S. is any indication, there will be plenty of takers when the U.S. version of the DUALphone goes on sale in mid-August. It will be available only via direct website sales at first (the website isn't up yet) with "distribution via retail channels ... announced at a later point in time" according to the RTX rep. If you're a heavy Skype user, the DUALphone is something you'll definitely want to check out.