I have both and wear them both (not at the same time). I prefer the tartan, but depending on where I am going, I may wear one of my plain kilts.

I have noticed especially with Utilikilts, it does get guys into wearing kilts, and with that, more kilts usually arrive.

Yes I do agree with Graham, age may have something to do with it, but also depends on where they live, and how they live life.