This morning, Microsoft announced an important milestone in the development of its next-generation smartphone platform, Windows Phone. The company has delivered a near-final, technical preview version of the system to developers in preparation for a broad, worldwide launch in the fourth quarter.

"Our software is now ready for the hands-on everyday use of a broad set of consumers around the world," Microsoft Corporate Vice President Terry Myerson wrote in a blog post announcing the release, "and I can’t wait to see how our developer partners take advantage of our new approach to smart design and integrated mobile experiences."

Myerson also took an implicit dig at Apple, whose own lack of testing has finally come back to haunt the company in the form of multiple, endemic hardware problems with the iPhone 4.

"The \\[Windows Phone\\] software has undergone extensive testing, in daily use by more than 1,000 people at Microsoft who have been using \\[Windows Phone\\] as their only phone for the past several months, and the more than 10,000 devices in our test labs," he noted. "We've been testing usability, battery life, network connectivity, and many other metrics for a long time. As a result of that work, I hope you will find the experience to be of surprisingly high quality."

That's what I've found. In my owns tests of the technical preview software this month, running on prototype hardware devices, Windows Phone has worked reliably and with excellent performance. More enticingly, Microsoft's new Metro UI, with its integrated panoramic hubs and touch-based interaction model, is like a breath of fresh air in a me-too mobile industry that's been bogged down for too long trying to ape Apple's increasingly tired apps-based model. Windows Phone isn't perfect—yes, it will lack features like copy and paste and true multitasking at launch—but I don't believe these concerns will deter actual consumers, either.

You can read my initial hands-on report of Windows Phone on the SuperSite for Windows. I'll have more information about Windows Phone in the days ahead.