Windows expert Paul Thurrott has launched a scathing attack on Microsoft's new Vista OS.

He accuses Microsoft of drawing a trail of broken promises and abandoned features in the release, castigating the firm for its "abysmal handling" of the project.

He writes: "From a technical standpoint, the version of Windows Vista we will receive is a sad shell of its former self, a shadow."

Thurrott seems genuinely angry. When he first saw Vista demonstrated he was full of optimism. He recalls his excitement at the transparent windows and the ability to embed media into documents and more.

His hopes are dashed: "Two-and-a-half years later, Microsoft has yet to ship Windows Vista, and it won't actually ship this system in volume until 2007," he reports.

For Thurrott, Vista hasn't lived up to the hype: "You'd have to be special kind of stupid to look at Windows Vista and see it as the be-all, end-all of operating systems," he writes.

"Shame on you, Microsoft. Shame on you, but not just for not doing better," he writes. "We expect you to copy Apple, just as Apple (and Linux) in its turn copies you. But we do not and should not expect to be promised the world, only to be given a warmed over copy of Mac OS X Tiger in return. Windows Vista is a disappointment. There is no way to sugarcoat that very real truth."

It's a shame - not just for Microsoft but for mass market computing, he reflects: "Windows Vista was Microsoft's first chance since Windows 95 to reach for the golden ring. It may be another decade before it tries again," he concludes.