Thanks for that infoTo Lisa and the OP:
Mighty Mice are great if you give yourself a chance to get used to it. the tracking is smooth and accurate and the 360 click-able scroll ball and side squeeze buttons are worth the price alone. the only downside is having to lift you index finger to right click as the casing is heat sensitive. but you get used to it after a while. i know lift my index finder on all mice out of habit!the battery life lasts one month for me using one lithium battery.