Comment 1: The Logitech in question sounds very similar to the Marble Mouse which is a current product. As you elude, different rodents suit different people. We use the Trackman Marble Wheel which uses the thumb, and can get tiring with extended use. The above Marble would be good for a change. Also many mice are quite small in comparison to some male hands and therefore a larger product is more suited. I would recommend spending a while in a shop trying different models prior to purchase. PC World has most on display, but cheaper prices are available buying online later. If funds are available I would even recommend having two (or more) mice connected, making use of serial, PS2 and USB ports.
Cordless is even better if a suitable model exists. Thus giving you the option to change movements regularly and enhancing usability if the PC has several users. Most of the products are unfortunately geared to right handed people, reducing choice, although there are specialists suppliers of left handed products. This is the Logitech link. http://www.logitech.com/home. Don’t forget that RSI Guard can also assist in mousing (eg auto click), and you can have it on two PC’s under the same licence.
Comment 2: I have found that trackballs give me the same problem as mousing and typing because they use similar finger movements. I tried a variety of options at my local Employment Office (they have a disabilities lab where you can try out a variety of ergonomic keyboards, mice & trackballs) and found that an Anir mouse was much more comfortable for me. It has a joystick design, and although it was a bit strange at first I am very happy with it, and it has considerably reduced my pain. I strongly recommend it.
Comment 3: I use Mousetool to click (with sparing use of the trackball buttons where this is more convenient), but overall I try to avoid doing too much mousing by using keyboard shortcuts etc. I occasionally use the number pad as a mouse alternative (using the somewhat eccentric/erratic MouseKeys feature in Windows). I should stress that my symptoms are not (God willing) particularly bad, so I am capable of doing more (than I really should). Also, I use VR (IBM ViaVoice) for most of my typing.
Comment 4: I find the Kensington Expert Mouse (programmable Trackball) very good, although it is high of the desk to accommodate the very large trackball. I use a large “Fellowes” gel-filled mouse rest to support the wrist when using it. The two websites are: www.fellowes.com www.kensington.com. The large ball is easily controlled with a very gentle touch using any fingers, it can be switched left – right very easily to rest the hands, and the 4 buttons are all programmable which is a real boon as I can’t click a normal mouse without pain. The trackball can cause a little pain after a lot of use, but its nothing compared to the mouse (my pains are limited to the hands BTW).
Comment 5:Thanks to everyone else for the Trackball advice, now I would really like to find someone who has used the foot operated mouse from Hunter Digital . Ps. The only thing I have done which helped and I can pass on is that I ditched my old desk and bought 2 adjustable height trestles + table top from Ikea (and I made a monitor stand). Maybe because I am short 5’4″ I found that, even with an adjustable chair at maximum height I could not get high enough relative to the desk surface. Now I can move the desk surface low enough and this made a big difference.