Paul Thurrott posted part 3 of his Windows Mobile 6.5 review

This shouldn't be surprising, but by mimicking its success with desktop versions of Windows in Windows Mobile, Microsoft has created a mobile OS that has many of the same strengths and weaknesses of its inspiration. Equally unsurprising, then, is the fact that Windows Mobile's greatest strength--the diversity of devices on which you can acquire the new system--is also its greatest weakness.

The solution to this problem should be simple, but it isn't. When Microsoft opted, at great expense both financially and to its credibility, to launch the Zune platform and undermine its years-old hardware, software, and services partnerships as a result, the company didn't exactly reap great success. In fact, if anything, Zune devices have accounted for a smaller share of that market each year since the platform has launched.

Windows Mobile 6.5 Review Part 3