There is very little difference between all of the above devices, they are all branded versions of a series of mobile phone made by a japanese company called HTC. I have a UK o2 XDA IIi which is also known as a Qtek 2020i, iMate PDA2k, MDA 3 (i think). checkout a site called www.xda-developers.com for loads of info on hacks etc for the HTC mobile PDA phones.