Like you and the linked article, I
really enjoy working with the WP7 development stack. I'm currently working (with 3 other devs) on a mobile application for 4 platforms (iOS, Android, WP7, and JQuery Mobile).
Even having skipped an entire sprint (~10 days) to focus more on Android, the WP7 app is progressing along further and faster than the other clients. Just having support for (albeit limited) databinding is a huge win. Plus, you get great looking apps pretty much for free with the theming defaults.
That said, I have access to a few Windows phones (HTC Surround, HTC HD7, and some keyboard phone) and I would not be able to switch to any of them over my Nexus One. Dealbreakers for me:
* The search button is locked to Bing (not configurable)
* The browser is not only IE, but a crappy offshoot of an old version of IE (I believe IE7 w/ a few patches)
* No Pandora