I've had this mouse since 2009, and have been entirely pleased with it. After a recent soda disaster, I've had to look into replacing both of my primary input devices -- keyboard & mouse. The keyboard is no big deal. I like it fine, but I'm sure another brand would also suit me without any major difficulty. The mouse, on the other hand, has become indispensable. And it's also fairly unique.Ever since using a trackball (not sure which brand) mouse on a laptop computer I had, I've been fond of the convenience of a mouse which doesn't need a bunch of clean desk space to function. My desks, traditionally, have been messy places short on real estate. A trackball was the perfect solution for me. This model Logitech mouse has worked flawlessly, and I can't imagine trying to grow used to any other flavor -- which is why, when I went to buy a spare one (today, January 24th, 2012) (my current one seems to have survived Colageddon without any major damage) I was a bit flabergasted to find a bunch of bottom feeders charging as much as $150 for a mouse I paid a scant $23 for, back in the day. There are even scumbags (sorry for the harsh language, but I can't think of any other way to describe the kind of profiteer who would charge such a price) asking $335 for one of these mice. You heard me -- three hundred bucks for a mouse! Well more than ten times what I paid!I have no idea why Logitech would've ceased manufacture on a device which functioned so perfectly and wish I'd picked up a spare back when the picking was good. This mouse was most definitely worth what I paid for it (around twenty bucks, in case Amazon censors my review and reviews any mention of price from it) but to charge more for this mouse than you'd pay for a brand-new low-end laptop computer is absolutely rickdickulous. I would be interested to know whether any of Logitech's current models are comparable to the old Trackman from a functional standpoint. I notice they seem to have abandoned the left-positioned trackball design, presumably in response to some namby-pamby whining campaign launched by sinister left-handed folks who felt neglected by the trackman's unabashadly right-handed design. Thing is, having the trackball on the left meant the trackball was where my thumb lives. And that's a good thing. Putting it in the middle means it's where *nobody's* thumb lives. And that's lame.Perhaps I need to design myself a flux capacitor, so I can travel back in time and pick up a few shipping containers full of old-school, proper Logitech trackman mice. I could make myself a tidy sum charging people for design done right. Rather than ambidextrous.Oh, and to all you sinister lefties out there, I realize there's a good chance Logitech changed the design for some other reason -- and I don't really blame you for the change. I was just teasing a bit. If my teasing was too harsh, I apologize. The last thing I want is a bunch of irate, sinister lefties out in the world itchin' to gun me down. Heck, I can't even keep my soda from spilling onto my desk -- how the heck does anyone expect me to survive a showdown with militant left handers?

I see that I'm hardly unique here. Like others who've posted reviews already, I bought my Logitech Trackman Marble back in 1995 or so when I bought my first Windows PC.So when I went GUI, like many of you, it seemed to me like a totally dumb idea to move a mouse around a desktop. It made much more sense to me to keep your hand on a stationary peripheral.At the time, the Logitech Trackman Marble was the only game in town if you wanted a trackball. This simple inexpensive little peripheral has outlived countless computers and has served me well for over ten years! Wow!So I was beside myself when some books on the shelf above my computer slipped and knocked a cup of Pepsi over my keyboard and Trackman last week. The keyboard? Eh! Keyboards are the proverbial dime a dozen these days. Big whoop. But my Trackman! I was frozen in terror. Do they still make trackballs? Or have mice totally won over? Or are they all ambidextrous now with the ball in the middle to appease lefties? I'm so used to using my thumb to roll the ball that I don't think I could get used to an ambidextrous trackball (and contrary to what others have said, I'm so comfortable using this type of trackball that I can frag in Unreal with the best of 'em using my thumb to aim with)!Amazon.com to the rescue! Much to my relief, Logitech still sells a Trackman trackball. The styling is a little more modern and "swoopy," but the design is essentially unchanged in 10+ years--and that's a GOOD thing! I ordered it from Amazon last week and find it fits me as well as my prior Trackman Marble. The Trackman Wheel is a wee bit smaller than the Marble and the mouse buttons are a little closer together--not enough to see, but my hand feels the difference. But that's no big deal, I got used to it after just a few minutes. Also, it comes with a driver CD, but Windows recognized it out of the box without having to install the CD--even the wheel. That's a good thing too because I don't like installing unnecessary software onto my PC if I don't have to. I can't praise Logitech enough! Highly recommended for anyone addicted to a thumb type trackball!Incidentally, after my new Trackman arrived and I breathed a sigh of relief that it is essentially the same design, I performed a little "surgery" on my dead Trackman. Removing the four little screws from underneath it, I disassembled it. Before you read on, don't try this on any working device--this was a shot in the dark on a device that I had given up for dead anyway. With the ball out and the screws removed, the shell pops apart easily and the tiny circuit board lifts right out--no prying necessary or risking snapping little prongs off to lift it out. Being careful not to break any of the delicate wire jumpers, I wiped the circuit board down with a damp cloth to get all the Pepsi gunk off. Then after it dried, I wiped it down again with a Q-tip dipped in rubbing alcohol to remove any residual moisture. The top and bottom plastic shell, as well as the ball, I ran under the hot water faucet for a few minutes (there's no metal parts). Letting it all dry out overnight (the slightest moisture on any electronic circuit will totally fry it upon giving it power), I reassembled it the next morning. Guess what? I plugged it back into the USB port, and it works perfectly! Better, actually, than it had worked for a long time. Being optical, the Trackman Marble never lost its precision over the years the way ordinary mice do after a year or so, but I was never really able to clean those little metal prongs in the ball socket very well, and the ball sometimes felt "sticky" even after cleaning the ball socket out. Picking the gunk off those little metal prongs in the ball socket with my fingernails never got it as clean as the "overhaul" it just received. So now I have two working Trackmans, both seemingly in brand new condition!So I'm going to go back to using my old Trackman Marble and put the new Trackman back in its box and save it for when my old one does eventually wear out.