Nokia recently launched its 4G capable smartphone flagship: Lumia 900. A large of reviews are now available at major media outlets such as CNET, WSJ, TheVerge, Forbes (Forbes consolidated others' reviews), and NYTimes. So far the opinions are quite uniform: it's not as good as an iPhone or high-end Android (such as Galaxy SII) but the phone is fast, sleek, and does the jobs it is supposed to do well most of the time. And it's $100 cheaper than the usual $200 price tag for the usual flagship models.
Most reviewers deplore at the shockingly primitive stage that Windows Marketplace is in right now. Of course, for those well versed in the Appstore with 600,000+ apps or Android Market with 450,000+ apps, Windows Marketplace is nothing (only 70,000+). However, for first time smartphone users, not getting Instagram on his or her phone may not be a problem. With Lumia 900, one gets lightening fast 4G, very pleasantly looking Windows Phone 7.5, intuitive interface, and strong, integrated social network platform "People".
With that, I think Nokia and Windows Phone 7.5 will enjoy a victory bigger than most anticipated. The later half of 2012, when more powerful dual core Windows phones enters the market with backing of more vendors (HTC and Samsung), the Windows ecosystem may truly be a valid competitor against Android and iPhone.