I think it's the difference between being simple, and hiding complexity behind towers of abstraction. In my experience OpenBSD goes to great lengths to rethink systems and purge intrinsic complexity. By contrast, Linux tends to merge complexity behind meta interfaces.
OpenBSD's approach appeals to me aesthetically, and I like the feeling that I could easily dive in and get to the bottom of the stack. There is no magic.
By contrast, I look at Ubuntu as a hot mess of code that I'll never understand, while simultaneously appreciating that I can click through the installer after a cocktail or two and be playing games on Steam in short order.
