I grew up with smaller micros, like ZX Spectrum 48k and Commodore 64, then I got my first PC and it ran DOS. I started using Windows 3.0 when it came out, and I've been a Windows user ever since. I tried Linux desktop a few times, but couldn't get used to it. I've never had a Mac, so I can't answer that part of your question, but I can give you my views on Windows GUI.

I find Windows 9x to be ugly now. Back then, I thought it was the best thing since sliced bread. Like I said, I didn't have a Mac, but I tried OS/2 Warp, and I hated it.

I think the Windows 9x nostalgia stems from the absolute usability fustercluck we have these days. Back then, the GUI was uniform -- you didn't have to guess which element did what for each app -- and it communicated clearly. You always knew if a toggle was on or off, if a button was pressed or not, etc. When a dialog popped up to open a file, a single Shift+Tab would take you to the file list, instead of silently and invisibly putting the focus on the list headers. You could move your mouse around without "helpful" hints popping up everywhere.

I would happily go back to these "obsolete" ideas of consistent and concise GUI design, but it won't happen. People have been harping on about this for years now, and things aren't improving. It's just not a priority, I guess.