*Update 13Mar2014: All Logitech software now installed and the C170 is still running fine on the backup PC.
*Original review (edited): An overall 4 stars because this is better for image quality than my old Logitech C500 and Microsoft VX5000 webcams. I just plugged-it into my backup Windows 7 PC, where I wanted it to replace a rather old and tired Microsoft cam. Perfect! A good image, and Skype liked it too. No problem for web chat applications using the Windows 7 drivers, updated via Windows Update.
I had first tried to install this on my main PC, to replace a Logitech C500. I had some issues here, even though I thoroughly uninstalled the C500, driver and software and rebooted the PC before installing the C170. I got an image in Skype, but it split the image of the people I spoke to into three horizontal bands. I repeated the installation with the same result. I then reinstalled the previous C500 and had the same problem ... but now it has resolved itself. No idea how. Will you have this problem? Probably not. But, just in case, you may want to set a Restore point before installing. Nobody else seems to have had a similar experience, so it's probably just bad luck.
Bottom line: give it a go. On quality grounds you won't regret it, especially for the money.