The first crop of Windows Phone 7 devices has gone on sale in Microsoft's home market, backed by heavy promotion by the company and its carrier partners.
US operators AT&T and T-Mobile on Monday started selling the HTC Surround, the Samsung Focus and the HTC HD7, Microsoft said. The LG Quantum and Dell Venue Pro will launch in the next few weeks.
AT&T is strongly pushing WP7 devices, devoting a special product wall with a dedicated touchscreen at most of its 2,200 stores, Forbessaid.
The operator has already introduced its U-verse Mobile video-on-demand service for Windows 7 devices simultaneously with the WP7 launch.
Microsoft could spend as much as $500 million on marketing, subsidies and other expenses to support the WP7 launch, TechCrunchreported.
Reviews of the first Windows Phone 7 release have praised the responsive user interface, but say it takes getting used to and is missing a universal search option.
Reviewers also complained about the lack of support for third-party multitasking. Engadget said the WP7 still feels a year behind market leaders by user experience and feature support.