Logitech Optical Trackball Marble Mouse

I received and installed the mouse less than an hour ago. I will only be discussing my experience thus far, and focusing on installation and instructions, so you may want to look at other reviews to get an idea of durability. Summary: Easy to set up, feels good in one's hand, compact, useful, inexpensive, but the Amazon product information was poor and almost caused me not to make the purchase. Also, the Logitech help is confusing because it provides only one set of instructions for all their models and leaves it to you to pick through the information that is irrelevant to your model.Amazon wasted a substantial amount of my time by including incorrect product information. First of all, the product info blurb said that the product requires batteries, which would have been ridiculous for a wired mouse and would have dissuaded me from making the purchase. However, since none of the reviews referred to batteries, I decided (correctly, as it turned out) that Amazon must have made a mistake. Secondly, I needed the mouse to fit into a narrow space on an extendable shelf below my desk, so the dimensions were important to me. The good news is that the mouse is actually a good deal narrower and shorter than the product information indicates, so it does fit, and doesn't force me to extend my fingers way under the desk itself. The fact that the mouse is so low (2 inches -- the only dimension that the product info got right) is great. Just wish the other info had been more accurate. I would have wasted less time researching the product and bought it sooner.I intentionally ignored Logitech's installation instructions, which asked me to power off the computer before connecting it and then to install the software. I hooked up the USB directly to my computer, which was already on. No puff of smoke, no hung computer, and I saved myself a good five minutes by not restarting. The mouse's rolling and clicking actions worked even without installing the software, but I couldn't figure out how to scroll with the mouse, so I did install the software.I found that the default "Universal Scroll" was not good for me, since it scrolls horizontally as well as vertically. Since I almost always want to scroll in a purely vertical direction, I changed to "Auto Scroll", and was glad I did. It's a little unintuitive at first, though. You have to press the button and wait a fraction of a second for the icon to change before you start scrolling. I also found that I needed to change the scrolling speed to the slowest available. I can imagine that people with slower reflexes (perhaps myself in a few decades!) would have liked slower speeds still. I don't know why anyone would like to scroll at their default speed, let alone faster, since the words become a blur.Finally, the Logitech one-size-fits-all instructions wasted my time by mentioning a lot of features that were not relevant to my model without segregating these sections from those that apply to all models. I'm not sure if their intention was to make me toss the mouse I'd just bought and buy one of the other versions, but if so, it didn't work. Ideally, they'd write a different set of instructions for each mouse, but failing that, they could do a better job of using special formatting to set off the model-specific information. Also, finding an explanation for the unusual terms used in the UI (e.g., "Document flip") took far too many steps, since "Index" and "Search" took me not to the relevant page, but only to a page that led to the relevant page.In conclusion: I like the mouse. Not crazy about Amazon's or Logitech's written material, or Logitech's defaults, but those are easy to get beyond.

I have bilateral Carpal Tunnel Syndrome and have had both hands surgically repaired within the last year. I do application design work and need to have very fine control over the position of the pointer. Not wanting to have a regression in symptoms, and looking for the most comfortable pointing device that allows me to work without moving my wrist, I've tried several different trackballs. I have bought the Kensington Expert Mouse Optical USB Trackball for PC or Mac 64325, the Logitech Trackman Wheel, and this Logitech Optical Marble Mouse. The Expert Mouse was very well built and included a nice wrist rest, but it was a bit too large even for my large hand. I still had to move my wrist around in order to move the ball and press the buttons. I used it for two weeks before giving up on it. The Logitech Trackman's ball is manipulated by using the thumb only, and I found myself straining in order to hold the ball steady while clicking the mouse buttons. The main issue here is my own limitations rather than a design flaw on the mouse. Due to the nerve damage I suffered in my right hand, I can't hold my thumb steady enough to use this mouse.The Logitech Marble Mouse is perfect for my needs. The design is the most comfortable I have tried and I am able to move the ball using my index and middle fingers while letting my thumb and ring finger rest comfortably on the left and right buttons. An added bonus for me is that the buttons are not as sensitive as most others I have used. This allows me to relax my hand and let the fingers rest on the buttons without inadvertently clicking. I am able to comfortably work with this mouse without moving my wrist at all. There are two additional programmable buttons that are well-placed so that I don't accidentally click them, but they are handy when needed. The mouse is well built and has a nice heft to it. The rubberized areas underneath keep it from wandering across my desk.I highly recommend this product to anyone who either suffers from CTS or wants to avoid developing it in the future.I'm updating this review (1/14/2009) now that I have had this device for some time.My CP did begin to flare up again, and I have finally settled on a solution. I removed the ball from this trackball, and use it with my right hand only to click. I then gutted a regular mouse to disable the buttons (so I could relax my hand and let it rest over the mouse) and use it with my left to move the cursor. Yes, mousing is now a two-handed operation, but it is the only way I can avoid the damage to my wrists. Ideally, I would love to have a flat touch pad for my left instead of the mouse, but I haven't found one yet.