Microsoft is so desperate to prove Windows Phone 7's worth in the fiercely competitive smartphone market the company's already giving technical previews to the press, months before the platform's holiday launch.Already testing Windows Phone 7 are Engadget, Boy Genius Report and InformationWeek, which got to use Windows Phone 7 or see it up close on a Samsung phone that will never be released. From these technical previews, you can get a decent idea of what's good and bad about Windows Phone 7. (Photos are from the evaluating sites.) Here are my gut reactions:Hot: UI Like ButterCall me superficial, but it's always bothered me how even the best Android smartphones don't rival the iPhone in terms of smoothness. I really think this can make the difference when drawing in smartphone shoppers, and with Windows Phone 7, Microsoft shows that fast, responsive interfaces aren't the exclusive domain of Apple.Not: Missing FeaturesWe've known for months now that Windows Phone 7 won't support copy and paste, third-party multitasking or HTML5, but it's always worth repeating. No matter how good a job Microsoft does on Windows Phone 7, these missing features will haunt the platform.Hot: The Virtual KeyboardEngadget and BGR both raved about Windows Phone 7's on-screen keyboard. Period and comma keys are always present, and there's even an emoticon button, but most importantly, the keyboard is reportedly quite accurate. With a virtual keyboard like that, who needs physical ones?Not: Office LimitationsIn theory, document editing should be the shining star of Windows Phone 7, with support for mobile Microsoft Office.But as Engadget notes, the software has a few major drawbacks: You can't change fonts or copy and paste, there's a limited selection of colors, and you can't create new PowerPoint documents on the phone. Users should not have to seek workarounds for these features.Hot: The Camera ButtonEven on smartphones, I like taking pictures with landscape orientation. The problem is that most phones require a sort of cat's cradle maneuver to hit the software shutter button while holding the phone with your other fingers. Windows Phone 7 remedies this issue with a dedicated camera button on the side of the phone, the same place you'd find the shutter button on a digital camera. This button can also be used to go straight to the camera when the phone is locked or turned off.Not: The Mystery of Xbox LiveMicrosoft's gaming brand will play some sort of role on Windows Phone 7, but the company has yet to show a cohesive vision for how it will work, and games are absent from the technical preview. News flash: Video games are huge on smartphones. Microsoft needs to make sure this feature doesn't fall by the wayside.Hot and Not: The Interface ItselfThe reactions I've seen so far on Windows Phone 7's interface are mixed. BGR tore apart several UI aspects, such as a frustrating phone app and the lack of a menu for jumping between apps, while Engadget praised the platform's unique but purposeful look and its ability to get out of the way to let users reach their content. I'll reserve judgment on Windows Phone 7's interface until I've actually tried it.