Nokia’s flagship Windows phone has been available for preorder since yesterday but has since been taken offline. The Lumia 920, which will run on Windows Phone 8, was available for preorder as early as this morning but after scouring Best Buy’s website (where exclusive preorders were available there courtesy of AT&T) it is nowhere to be found. There was no word on a shipping date but Best Buy noted that it would “ship when available.”

Business Insider has two theories as to the strange disappearance of the Lumia from Best Buy. They noted that, “1.) Nokia and AT&T have yet to formally announce pricing and a release date for the Lumia 920. It’s possible Best Buy jumped the gun. 2.) Best Buy sold out.”

It is possible that the culprit could be a mix of both hypotheses. But either way it shows that the smartphone is either going to be a huge hit, or that Best Buy thinks it’s going to be a huge and they’re getting antsy in their pantsy.

For a two-year contracted price of $149.00 (less than the iPhone 5) users will get a 4.5-inch 1280 x 768 HD touchscreen display, a Snapdragon S4 1.5GHz dual-core processor, 1.3GB of RAM and 32GB of storage. There will also be 4G LTE connectivity, NFC capability, and a front and rear-facing camera–megapixels and 8.7 megapixels respectively. It will run on the upcoming Windows Phone 8 operating system. The reason there’s no definitive shipping date is that AT&T and Best Buy are likely waiting for the formal Windows 8 announcement on Oct. 29.

Early reviews of the mobile device are mixed at best:

T3: “It’s difficult to separate the two factors when examining the Lumia 920. As stated, it’s clear from the launch how close the firms have become in their respective smartphone pushes. The device will not just be Nokia’s flagship handset, but it’s also bracketed as something like a showcase for what Windows Phone 8 can do – much like the Galaxy Nexus was for Android. In all, the device looks like an imaging powerhouse, and has a number of interesting features in its own right – however the role it will play in the early first shots of Windows renewed push for a larger share of the smartphone market will be key.”

GSMarena: User votes give it a 40% for popularity, 8.8/10 for design, 8.7/10 for features, and 8.8/10 for performance.

Seeking Alpha: “At this point in the smartphone product cycle, commoditization is working strongly against Nokia. On September 5, Nokia produced a demonstration for its Lumia 920 phone in New York City. Wall Street remains largely unimpressed, as traders immediately entered orders to sell off Nokia stock towards a 15% loss that very same day. The Lumia 920 is a solid, but far from revolutionary machine. As such, Nokia will not be able to ship out enough units to counteract a 30% decline in smartphone sales over the prior quarter.”

It doesn’t look like the Lumia 920 is separating itself from the field in terms of features, but the pricetag is clutch. Let us know how you think the Lumia 920 will stack up. Can it compete with Apple and Samsung? Will it outperform its predecessor, which Greg Gomer noted two weeks ago had “data connecting problems”? Tell us your thoughts in the comments section below.