Eww I hate trackballs... but my friend swears by them. He's been using some Keningston supertrackball for the past several years. He was raping everybody in MechCommander or something a while back and they are all like "WOW WHAT JOYSTICK DO YOU USE?" and he's like "lol trackball kiddies."
I much prefer the mouse.
Batteries do suck danielson... but this particular keyboard & mouse set says that keyboard batteries last 6-12 months and mouse lasts 3-6. After these that came with the keyboard run out, I'm gonna put in these Duracell super batteries that I got as a free sample with the "normal" ones. =)
All of these special function keys are cool too... they have a "Finance" button and I linked all of my credit card online access accounts to it.
Talk about a good usage of $100... heheh
-Warik