#Levelled opinion from experience or cited fact is both valuable and welcome.
I spew my opinions all over this site and it's usually warmly appreciated. That's because my opinions, when I give them, come from my experience. Why am I not tripping over "primarily opinion-based" more often? Let's look at the reason. Emphasis mine.
Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise.
Many of the opinions being exchanged in this question are those of programmers who have used both Ubuntu and Windows and are well pitched to offer their professional opinion. There are posts and comments both against and in favour of Windows. People are giving reasons. Things have an unexpected level of balance (given where we are). People are being objective about their subjectivity.
What's best is we have levels of quality where the voting helps pick the better answers out from the less good. The system is working. I know there's been some concern about ramble in the comments here but I'd be happy with a hundred answers if they all had value and in that vein we can vote to prune out the weaker answers.
We should reserve close-opinion for discussions like "What should I set my wallpaper to?". No expertise will ever help there, nor will it help another user. It's a fishing expedition in a barren lake.