Yes, microsoft windows. I use version 8.1 and while most end users loathe the interface I've studied the "windows" key and "context menu" key and found it quite fast to perform all my daily operations (except web browsing) mouse-free.
My experience with linux is that some programs are great but too many dont follow standard on very common keyboard operations such as search, tab navigation, context menu. Also it seems many of these desktop windows managers such as ratpoison come with default key mappings that conflict with many of my application's default key mappings which forces me to re-configure.
I invested some time customizing key mappings that would alleviate the issues, but I have a large stack of actual programming work I need to get to, and after awhile I just felt like I was trying too hard at it and decided to go back to the system that works for me. I would like to learn a little more about developer's mouse-free success with linux, vim, browsers and ides such as intellij. 2 years back when i researched this it didnt seem like a very important issue to many people, but to me the little bits of speed gained from keyboard shortcuts add up into great savings in time and cuts in repetitive movement and I consider it to be a crucial part of any development system.