The good: The hardware on my Lumia 822 seems solid. The OS is quick, responsive, and a real pleasure to look at. The only app I couldn't bring over from my iPhone 4 was my PNC banking app. I really like their implementation of Xbox Live and Skydrive. I think podcasts in Xbox music is a **** of a lot better than Apple's podcast app.
The bad: The "other storage" problem, the fact that this little unpatched issue has made people reset their phones to be able to install apps is unacceptable. No messaging privacy, my iPhone toast said the name of the person and "text message", my Palm Pre+ did the same thing, doesn't seem like it would be too hard to throw this in. They got rid of Zune as a desktop sync client, it just seemed unnecessary, rename Zune to Xbox Music and throw in more green if you wanted to keep the branding consistent. No way to close apps from the multitasking screen, add a red X or let you drop them off the bottom of the screen like Windows 8, they made the multitasking look a bit like WebOS but left out the satisfying way of closing apps.
I like Windows Phone, but with the negatives I listed being basic things other established players get right, I might bounce back to the iPhone in a year or so if they don't makes some decent improvements to the OS.
With Blackberry stepping up to the plate with their last shot at staying alive and Ubuntu and Firefox waiting in the wings to grab what they can, Microsoft really needs to get aggressive if they want to stay in the game