I put value in being efficient. The WP7 interface is smooth, quick and responsive. I have a better version of Office than is available on the iPhone or Android. The Microsoft cloud offering for syncing files gives me 25 GB, and all the applets that I need and want are available despite the rumored 'Lack of Applets.'
At the time I went with WP7 it was primarily because I needed to sync with multiple Exchange organizations, and it was the only platform that allowed it. I don't know if that is still true. But I quickly learned that WP7 helps me be more efficient than my Android phone did. Updates to the phone have been seamless, and there is a decent choice of hardware -- unlike Apple.
Unfortunately, hardware choice seems to also be the problem with Android and WP7. The iPhone is rumored to be more stable because it has a death grip on hardware. The user sacrifices choice and functionality for stability. In reality, I've never had an issue with my WP7, nor my family with their Android devices.
Last but not least, WP7 is not as cool as the Apple iPhone, but I'm already cool.
My boss wanted a Windows phone believing it would sync with his e-mail and calendar on his Win XP computer. He wound up buying a new computer to get it to sync at all.
I have an Android phone and an Android tablet, and find them easy and functional. I have used the Win 8 developers' edition and if the Win 8 phone interface is like it, no thanks.
Finally received my HP Touchpad with Web OS and wish HP had continued to develop with that OS. My impression of it is very positive.
Droid is a mess. Droid is for people who want to play on their phones day in and day out just to figuring the darn thing out. Droid is too fragmented -- stuff is all over the place!
Windows Phone 7 is simple. You can figure it out completely in five minutes or less. The integration of common apps such as Facebook works better than I thought. Love the live tiles GUI. iPhone is nice, but needs a GUI upgrade and more integration. iPhone also needs to come to T-Mobile -- the cheap network.