We have varied experiences with our devices, and our opinions are based on our personal experiences as they should be. Some users are very satisfied with their experiences using the same device/platform other users are very disgruntled with. I respect other opinions, and believe the person who posts a negative opinion did indeed have a negative experience using a device, and/or OS.
I fall into the category of a very satisfied WM user. I have owned about a dozen WM devices (yeah, I am a gadget geek), and have enjoyed using them all. I was reluctant to purchase my first PocketPC because I heard the horror stories about the devices, and ActiveSync. I was pleasantly surprised by how stable, and easy to use my first WM device was (an Audiovox Maestro), and enjoyed the plethora of mature 3rd party apps available. After about 16 Palm OS devices (told you I am a gadget geek

), I switched to WM. I rarely have to reset the devices, they do everything I want from a handheld, and (please no flames), I like the interface. If you have used a Windows desktop, you can use a WM device. I have tried utilities, and programs to spruce up the interface, but usually end up uninstalling them. If you prefer a more graphical, or sleeker interface, fine - I respect your choice, but it is not for me. Most devices came with a free Home application that had big, colorful icons, but I always returned to using the Today screen. 95% of my WM (and Palm OS as well) use is via finger navigation without a stylus. The stylus is usually only used for selecting a link from closely packed links on a webpage.
I have added 3rd party apps for productivity purposes, not to spruce up the interface. I doubt the 3rd party apps I use (databases, html editor, FTP clients, slingbox, etc.) are standard on other platforms. I do use CorePlayer for videos because it can play just about any video format without conversion. Other platforms may have a better standard media player than the one included with WM, but can they play just about any format video without conversion? If not, I would be purchasing CorePlayer, or its equivalent, for other platforms as well.
Pocket IE, what can I say - it is old, and needs an update. Pocket IE does a real nice job on the mobile web, but a poor to fair job on full internet pages. 90% of my web use is the mobile web by choice on any device with a <5" screen, and Pocket IE is fine for the mobile web. I do not like horizontal scrolling on any device, and panning is horizontal scrolling by another name. When I do need the "full web", I use Opera Mini (free) which does an excellent job on both the full, and mobile web.
If another platform meets your needs better than WM, or you find WM unstable, it is understandable why you switched. For me, WM has been very stable, and meets all my needs.