Sascha Segan at PCMag.com:
The LG Quantum could be a quantum of trouble. The first Windows Phone 7 device with a full keyboard that will be sold through U.S. carrier stores, it has a balky sliding mechanism and a really bizarre keyboard layout that could kill its appeal.
Windows Phone 7 also just doesn’t seem to be designed for phones with landscape-format, sliding keyboards yet. Too many of the Windows Phone 7 screens don’t rotate, leaving you craning your neck to try to operate the phone at a 90-degree angle.
Maybe that’s why Dell opted to go with a portrait QWERTY slider on its Venue Pro.