That soley depends on the end user. Treo 600 is supported by the Palm OS. However, the Samsung i600 and i700 are both supported by windows mobile. Being that i work for verizon wireless and the windows mobile was released much before the Palm OS, im more familiar and more comfortable with the windows mobile myself. To me its easier cause it resembles a windows format im so used to off of a PC. Like i said though, solely depends on the End user.