Suggestions for and comments on trackballs?

[Richard Cobbe <cobbe@directlink.net>]

Greetings, all.

Over the last several months, I've been having increasing pain in my
right wrist.  A co-worker suggested that this is due to problems with
standard mice and recommended that I try a trackball instead.

So, I'm looking for a trackball that will work well with potato/X.  My
primary goals:

* at least 3 buttons that work in X.

* I'm using potato and kernel 2.2.18, so I'd need a PS/2 connector.

* the ball should be under my fingers, not my thumb, as it generates the
  most pain.

* Compatibility with gdm is not an issue, as I never use it.

* Other random features, like scroll wheels, extra buttons, and wireless
  connections, are extra.  Ideally, I'd like to avoid these, as they
  probably drive up the price, but I'll take them if I have to.

I'm looking at the Kensington Expert Mouse, Kensington TurboRing,
Kensington TurboBall, and Logitech Cordless Trackman.  (All the other
Logitech trackballs have the ball under the thumb or only 2 buttons.)

What experiences have people had with these devices under Linux?

Do people have any other recommendations for trackballs (or other pointing
devices, for that matter)?

Thanks kindly,

Richard

(I'm subscribed, so no need to CC me.)