I recently went to Circuit City to test out the Logitech DiNovo. While I was there I tested out several mice to see if there were any particuarly quiet ones. I tested various Logitech, Microsoft, and other mice. Kensington had several models out, many derivations of a line called the Pilotmouse. Of all the current offerings, their plain vanilla Pilotmouse wireless 5-button mouse seemed to be the best of all of the models on the floor.(not the special edition, wired, pro, laser, special edition, 3-button, etc)
The mouse is similar to the Logitech MX-series, though it lacks some of the buttons on top; the buttons that are usually covered by the top of the hand and are useless anyway.
The two primary buttons are covered in a thin rubber and are nice and quiet; compared to every other mouse I have tried, they are nice and quiet, MUCH more pleasant than Logitech or Microsoft mice, and they make using Windows and any other programs much more pleasant without the sharp clicks of other mice. The "clicks" are nice and very muted compared to other models, a joy other models lack, the absolute best thing about this mouse.
The side buttons, however, are a different story. They are noticably louder than the ones on the MX900, and feel somewhat hollow and lacking of mass. They feel almost cheap compared to the Logitech series. Also, they are reversed compared to the MX series when web-browing; the rear button goes to the next page, and the front button goes back to the last web page. If you install their software, you can easily remap this keys to the "proper" way. Also, the buttons seem to be a bit more spaced out from each other than the MX series, so you'll need to adjust a bit to make sure you push each button instead of the plastic, really only a minor complaint.
The scroll wheel is louder than the MX900. Not unbearably so, but still a regreatable flaw in this mouse.
The scroll wheel butto, not the scrolling portion, is louder than the MX900 but is lower in pitch. I.E. it's not as clicky sounding, but it is somewhat louder.
The mouse is also somewhat skippy when moving the cursor slowly, and to some extent when moving quickly . It's not very precise compared to other mice such as the MX-series. I've even tried it on white paper, it helped slightly, but not a lot. I've sent an e-mail off to Kensington to see if this is normal behavior or not; I did buy this from CC's floor model, so it's possible that people playing around with it might caused this problem.
The mouse doesn't seem to be in production anymore, it's no longer on Kensington's webpage, and I got the last one at Circuit City; they told me they're not ordering anymore, but I suspect that this is because it is no longer being made. The original price was $20, but they sold me the floor model for a little over $12.
To sum up, this mouse has a bunch of bunch of flaws. However, the primary "SPCR feature" are the two primary buttons. If you don't really use any buttons but those, and you don't need superfine precision, I would definetly consider getting this mouse. It doesn't cost a whole lot, and depending on the store, you can take it back. I'm not sure if I'm going to use this as my primary mouse, given the overall flaws, but the sound of the 2 primary buttons makes normal computer use so, so much more pleasant than ANY mouse I've ever used. Given the low level of noise of everthing else in my system, with the exception of my cheap speakers and my printer when active, I find the normal click noise of my MX mice to be noticably annoying.
So overall, I'd give it 6 out of 10, counting the precision and sound aspects. When it comes to the 2 primary buttons alone, I give them 9 out of 10.
Asus P4C800 Del., P4 3.0 Northwood w/Scythe SCNJ-1000 Ninja (fanless), Antec P180 black SPCR edition w/Acoustipack V.2 Deluxe; BBA X800 XT PE w/Zalman ZM80C-HP and 92mm Nexus; Samsung P80 120gb Smart Drive 2002 on foam; Raptor 74gb (turned off); Antec Phantom 350w; 2x120mm Nexus @ 670rpm, diNovo keyboard, Thanko Silent Mouse http://forums.silentpcreview.com/viewtopic.php?t=24308