Sitting at someone else's machine in work, at the moment. He has a trackball mouse installed so I thought I'd give it a go. Here's a picture of it:



It's definitely more comfortable then a regular mouse. I hate it when you run out of space on you mouse mat, so you have to pick up the mouse and place it back down in the middle; you don't have this problem with a definitely. On the negative side, I don't have nearly as much control as I would with a regular mouse, that might just be because I've only been using it for one morning though.