As was widely predicted, the Windows Mobile 6-powered HTC Herald slider will indeed be coming to T-Mobile—in fact, you can snap one up starting today. I had a chance to spend several days with the new Wi-Fi Windows Mobile smartphone—now dubbed the Wing—and while it's certainly crammed with features, it's also hobbled by sluggish performance.  

First, the good stuff. The Wing ($299 with a two-year service agreement) comes packed with an impressive arsenal of smartphone features, including Exchange ActiveSync and Direct Push support for corporate servers, Bluetooth, the mobile versions of Windows Media Player and Internet Explorer, a microSD memory expansion slot (conveniently located on the left spine of the phone), a two-megapixel camera, and a quad-band GSM radio for placing calls on worldwide networks. There's no built-in GPS navigation or 3G (T-Mobile has yet to roll out its own 3G network), but you can get high-speed data over the built-in Wi-Fi receiver—nice for anyone with a wireless home or office network.

The Wing is also one of the first smartphones in the U.S. to ship with Windows Mobile 6, the latest version of Microsoft's mobile OS (the slim T-Mobile Dash just got a Windows Mobile 6 update of its own). That means more editing options in the mobile editions of Word, Excel and PowerPoint, tight integration with Windows Live messaging, and—finally—full support for HTML-formatted e-mail messages, which worked like a dream in my tests. Tapping out messages was a piece of cake thanks for the Wing's roomy, slide-out QWERTY keypad.

All well and good—but unfortunately, my review unit of the Wing was slow as molasses. Programs and menus screens often took a few seconds to refresh, and buttons took too long to respond; on some occasions, I kept pressing an on-screen button with the stylus thinking the phone had frozen, only to have menus pop up a few seconds later. Indeed, this is probably the most sluggish smartphone I've tested since the originally shipping version of the Motorola Q, which drove me nuts. The Q was eventually fixed with a software patch, so hopefully one will be forthcoming for the Wing; in the meantime, however, be warned.