LogitechOptical 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 used this mouse for a month and a half, and so far it's smooth sailing. I bought this mouse to mitigate the constant wrist pains I had been getting due to excessive PC gaming. The pain is completely gone, and I can still compete against traditional mouse users in online gaming (I regularly get the highest score on TF2 with this mouse). It took about a week to get used to, but I am now as adroit at using this input device as I was on my traditional optical mouse.Some thoughts about the Logitech Optical Marble Mouse:-When I first used this mouse, the ball didn't roll smoothly. However, after a few hours of use, this cause of concern disappeared.-Cleaning is simple and necessary, as the rolling action becomes very stuffy after a couple days. I pop the ball out and rub my fingers against the three contact points, on which the ball glides over, to remove debris. I then polish the ball itself with my shirt and pop it back in; less than 30 seconds of cleaning.-There is no scroll wheel. It was perturbing at first, but I have gotten used to it. I click one of the side buttons and the software scrolling comes up; move the cursor up to scroll up and vice versa.-I set the scroll button to open and close tabs in the Firefox browser as I had done this with my previous mouse. For some reason it requires a double click now instead of a single click.-It saves a lot of space on my desk.I urge users who have wrist pain to buy this type of product to prevent any future carpal tunnel complications. Others who do not have wrist pain would be prudent to buy one too as they may have symptoms later.My only complaint is the lack of a scroll wheel; the middle right button could have been replaced with one. At this price point, however, this is a moot point.This product has my endorsement.