[astroglide]

i love the "big ball" approach with the kensington because you can vary the way you actually move it as well. it's symmetrical for perfect left-handed usability too. when i first got it i had a right hand mouse and tried using the trackball as much as i could tolerate it on the left. i switched to right-handed trackballing and never went back, only took a day or two of adjustment (and i'm a guy that's been using a keyboard/mouse like 10 hours per day for the last 10 years).