For me it was the OS that mattered the most. In the case for the early 8-bit computers it was how open they were about the system, so you could get into the guts and make things work. For me the top of the heap was Commodore, Apple, and to a lesser extent Tandy. The absolute worst in this case was TI who didn't give any access to the guts of the system. I wasn't exposed to the IBM side of things until the mid 80s, but didn't really care for DOS.
By the end of the 80s I think the top of the heap was Amiga DOS. It didn't matter what I wanted to do, it never got in my way. By this time I had a lot more experience with Unix based systems and the UI was so much better than anything I had used before, even MacOS. By the early 90s I was already using virtual desktops with OLVWM on Sun systems. I didn't have any interest in Microsoft DOS or Windows at the time, even though I was forced to use them at work.
In fact I have never owned a Windows computer, I went from Amiga -> MacOS -> Linux and have never looked back.
Although I'm still using a Windows laptop at work.
Jason