A number of outlets are critical of the Motorola Wi-Fi/cell phone: TechDirt and TheFeature emphasize how limited the phone's use will be because it only operates on 802.11a. Also, as we noted yesterday, it sounds like this platform would make a tough sell because it requires APs from Avaya and Proxim or upgrades to existing Proxim APs.
The solution isn't ideal and neither is the HP/T-Mobile device, which doesn't include voice capabilities over Wi-Fi. These are pretty typical first attempts and they'll certainly improve with future iterations. However, the enterprise solutions like Motorola's will have a tough road ahead of them. Cellular operators are typically very slow to embrace change, especially anything that may be perceived as threatening their voice business, which voice over Wi-Fi may. I'll be interested to see which operator Motorola actually launches this with and which enterprises actually use it.