(This is a response to
an InformationWeek article. I couldn't get the comment system to work, so I posted it here instead, since I'd written it)
I switched to Linux in early '96, when Windows 3.1 wasn't meeting my needs. I think that Linux is a good choice at the point when you're going to have to put in retraining effort anyway. So long as it works, keep the same operating system. But remember that MicroSoft doesn't release new versions of most things; they change enough things that more training is required in order to use anything new.
As you said, the change between Windows 95 and Windows 98 was difficult for some users. On the other hand, since I started using Linux, there has not been a change of that sort to anything I've used, with the sole exception of Netscape.
This isn't to say that the OS hasn't made any progress; it's just that everything I've been used to having continued to work as I expected. All of the progress has been improvements which do not interfere with existing behavior: devices which didn't work now work; the system is faster and more responsive; the graphics have improved.
I think Linux is a good idea because it is Free Software, which means that you'll never have to get a new version of anything unless you want to, and because it has gotten sufficiently advanced that there will probably be ways to do everything your company wants to do. I wouldn't switch anything over to Linux if it is currently working, but I would use Linux instead of a new Windows version on new systems.