Originally Posted by 1stRaven 
Windows mobile? I just upgraded my touch diamond for free to windows mobile 6.5 and switched on the features that I wanted. To save some room, I can also remove those bits I don't.
Not a good argument. While I'm a WinMob user (and fan), I certainally wouldn't advocate flashing a custom ROM to anyone that wasn't cumfortable with the posability of bricking their handset.
Also I don't know what the legal issues are with custom ROMs, but I suspect MS only turn a blind eye to it because it is such a vibrant community that probably results is far higher sales of Windows Mobile devices. You payed for a license of whatever OS came with your phone, not for the updates that are only issued to manufacturers. Meaning that running 6.5 on your 6.0/6.1 device is not legal. It
is like downloading Vista and installing it on a XP machine.
Many choose WinMo purely because of unofficial ROMs - Granted it is a survey conducted by an enthusiast website, but it does highlight what I said.