I have not used the MS touch mice, but I have had the misfortune of using mice without a scroll wheel or middle button.
If the middle button does not work, you can easily remap the functions to keyboard buttons but it then forces you to have both hands busy all the time (I like doing CAD with the mouse to rotate and so on, while I hold a physical component or pencil in my other hand for example).
A laptop touchpad creates a similar situation - without proper scroll wheel tactical feedback you tend to exaggerate the movements resulting in a frustrating experience overall.
So regarding touch mice, I would advise against it. Or, if you get a touchy feely mouse, at least get an el cheapo mouse with a real scroll wheel for CAD. I find 'gaming' mice work quite well for CAD because of the extra buttons. I often use a logitech marble mouse for office work and a MX518 for CAD - leave both plugged in at the same time - the clever Logitech drivers detect which mouse is active and activate those specific settings.
Another thing to consider is your preference for a scroll wheel with continuous or discrete motion - i.e. does it click like a ratchet as you rotate it or does it rotate smoothly? I prefer the ratchet scroll wheel. Some Microsoft mice do not have a ratchet scroll wheel.
A '3-D' mouse (see
) is a nice addition if your main mouse is not up to the task.
Adriaan.
I am a Mechatronics Engineer from South Africa.