One person's experience with Microsoft Windows Mobile software:
As an owner of a Windows Mobile PDA (Dell Axim x50v) I can say authoratatively that Windows Mobile software sucks in so many ways it's hard to count. The OS is buggy, slow, an so severly crippled in areas that desktop users take for granted that it is physically painful to use. The software selection for add-on programs is so diminuative that when I switched from PalmOS, I honestly thought that I had to be missing some secret community of developers. I couldn't believe that 1) there were no Windows versions of so many of the Palm apps that I had found essential, and 2) there was no active community of programmers and hobbiests trading code and writing scripts to do all the little things that hadn't been included in the OS.
The Windows Mobile world is dominated by a very few developers who write commercial software for profit. The wonderful selection of little free/share-ware apps that exist in the desktop and Palm world is totally non-existent in the WinMobile world. In addition, MS makes it exremely difficult for the hobbiest to "play around" with the devices and this keeps many who might be interested from even bothering.
Some examples: There is one, and only one, program that can be used to completely backup your Windows Mobile device, and it is not included with the OS. This program must be bought, from a third party, and the WM 5.0 version took 4 months to be released after WM 5.0 was released.
To "Active Sync" your WM 5.0 device you MUST have Outlook or Outlook Express, not only installed on your windows desktop, but it MUST be the default email client.
There are only two usable alternatives to the internal contact/calender management programs, both commercial software, and almost no external script abilitiy to customize these apps beyond the limited choices offered by the developers.