There are lots of articles and reviews out there that do a good job of making a fair, informed case for Windows Mobile - whether by itself or in relation to competitors like Apple and RIM. Perhaps we can start capturing them in this thread? Be a cheerleader if you must, but more importantly, share what you know!
Here's a wonderful essay I found while researching something else. It was part of the "Smartphone Round Robin" at WMExperts. Reviewer Dieter Bohn and several other mobility experts traded phones over the courses of several weeks, and so got a taste of the entire smartphone marketplace through day-to-day experience. Very cool! Needless to say, Dieter was VERY happy to come back to his WM phone.