I have just bought the w810i and after carefully checking all three of these phones together, I find that the buttons are completely different to all the other models of this range. They are far better on the w810i, as is the joystick, it has directional keys around the joystick which the other models dont, which is about the first thing that goes on these types of phones. Also it has the radio and walkman, but the k750 has the radio and you can put mp3 on it, it is not a walkman like the other 2. The w810 is also a little more powerful than the others. Hope this was helpful for you.