This is the trackball I use on pretty much all my computers at work and home. It works equally well for either hand.
The thumb does all of the clicking while the Pinky does the alt-clicking. I've had a sore index finger from mousing but have NEVER found my thumb gets sore using this. Probably just the way the thumb is built??
All the ball action is with the index, middle, and ring fingers. This spreads the load nicely and lets you roll across the fingers when going from one side of the screen to the other.
Like many DAW'ists, I minimize what I install on the PC, so I don't install the Logitech drivers any more. I don't know if this driver feature still exists: you could click both buttons and the ball becomes a scroll wheel, which worked brilliantly. You had precise line-by-line scroll control yet could jump many pages with a free roll of the ball. The page-up/down and arrow keys for scrolling work fine for me anyhow. Plus that varies the actions you are doing, which is recommended by the ego specialists.
I have an old gyro mouse that works in the air and I found it difficult to use, and hard to be precise. Maybe the newer ones are better, but I can't imagine holding it in the air for hours at a time. Plus I jump between the keyboard and mouse constantly - would have to put it down all the time.
I agree with Jim that everyone is different and you have to find what works for you. And some people are much more affected by bad ergonomics than others. However, I hold with the contention that the the proper ergonomic workstation configuration and equipment, used correctly, is going the be the best for the majority of people over the long run, and cause the least physical problems.
So, Treefight, I ask you to consider if maybe it's much more posture/ergonomics causing your problems than repetitiveness stress.
If a body is used to poor posture, it's uncomfortable to use good posture. And it takes a long time to strengthen the body to use proper posture. But I have found it to be worth it.
I am sure an ergonomic keyboard to be a must for good ergonomics because it keeps the wrists in proper position. I would argue that the trackball I use (and I see many others here use) is the most ergonomic mousing device (if used correctly).
IANAD
ORIGINAL: Treefight
Xavier - your post is interesting and it's something I want to try, the left hand thing. One question: did you use the "normal" trackball with your LEFT hand? If so, how, specifically? Or do they sell left-handed trackballs?
It's a bit weird to use a regular trackball with the left hand - at any rate, the idea of using the left hand for the mouse is very very intriguing b/c it's the mouse that's the biggest problem.
Also - what about the air mouse?
Or the one that looks like a joystick - saw it on some specialist site, not something they sell at Staples or even a computer store.
Thanks so much.