Folders are broken in every graphical shell I've tried with the exception of RiscOS (does Rox use the same metaphor?)
The "search" tool is a reasonable solution for "Open" (and the Win7 one works remarkably well---in Gnome the command line is quicker: e.g., evince "`locate myfile.pdf`").
The main problem is the "Save As" dialog box; where you have to re-navigate to the folder that you already have open on screen. RiscOS presented it's own "virtual" folder view of the file to save, and you just drag it to where you want to save it.
Don't even get me started on Ubuntu's enforced $HOME directory layout. (Fortunately it's still overidable)
As others have said, I'll try it; but I'm not planning on adopting it.