"but seems to be picking up nicely"
Ah yes, yet another member of the "give MS a fair chance to catch up" brigade.
MS are not the late comers to phone space that need a chance to catch up. MS got into phones in 2001 or so and have been in phones twice as long as Google and Apple.
In 2001 they pretty much had the phone space wide open to them (except for BB doing the corporate thing). They took their lead and just dicked around. They made another go of it in 2008 or so with the Kin phone which was withdrawn after 2 months.
Over the last couple of years we see companies with a huge commitment to Windows CE space getting very skittish and making a break for Android.