Comparing the iPhone to Windows Mobile isn't a good comparison. Windows Mobile has been around for a LONG LONG time. With over 10 years of a non controlled environment, apps will be all over the web - just like apps for the PC. The iPhone is controlled by Nazi's who are very rigid and strict about everything...
-Mc
Personally, I feel this is one of the reasons why WinMo devices become so unstable; people making apps/ROMs available without any control and not being 'quality' checked. Of course the WinMo OS itself has a lot of problems in itself too.