I'm a T-Mobile Samsung Omnia owner so I'll just be patiently waiting until the update comes (and hopefully it shouldn't be any longer than a fortnight).
I agree with BigM. As an overall experience, this is the premier OS. It's unparalleled integration with social media and Skydrive, efficient configuration of tools such as Office and the camera function, speed of web browsing, intelligent approach to multitasking to optimise battery performance, usefulness of the live tiles concept and sheer elegance and intuitive use make it streets ahead of iOS and Android.
I mean really, the dominance of those two OSs compared to WP7 just goes to show the power of marketing. iPhone and Android handsets advertising is everywhere constantly. The same can't be said of Windows Phone. As earlier pointed out, much like with Android, all that's now needed is one of the OEMs to produce a really breakthrough handset that creates a buzz and has strong sales. That, just as with Android, will trigger a domino effect and it really should help build great momentum.
I really think HTC and/or Samsung should stick their neck out whenever Nokia eventually churn out a knockout WP7 handset and produce something that's every bit as impressive, from a hardware perspective, as their best Android handsets and then work with Microsoft to promote the hell out of them. Heck, with all the IP and malware issues that already do and will affect the Android OS, nevermind the Motorola buyout, the likes of HTC and Samsung really need to move away from having nigh on all their eggs in one basket.
I think 2012 is going to be utterly fascinating in terms of how the smartphone market, both domestically and worldwide, develops and evolves. I have a feeling, though, that it will be good to Windows Phone.