I just picked up the Touch T400 mouse and have a HUGE complaint about the 6.51 setpoint software. There are no button profiles. The mouse itself has a glide pad in place of the wheel so you touch for horizontal and vertical scroll. That is nice although so far not as smooth as a physical wheel....maybe just a learning curve.
There are also two buttons under the glide pad - one at the front and one at the back. So technically this is a 4 button mouse. Unfortunately the setpoint software only lets you configure two basic and useless options to these extra buttons - making them flip through apps or launch start. And, unlike the MS mouse software, you cannot set up specific profiles for games/programs. So if you setup a button as Start in Win8 it will always stay that way even when you are in a game or app where jumping to start is not an option you want at your fingertips.
So, just a word of advice, stay away from the T400 if you want anything other than a two button mouse with 4 way touch and a quick 'start' menu button. It technically has 4 buttons but is bare bones worthless for what Logitech lets you configure them for.