And what about props? I find positioning "junk" items like boxes barrels rocks bushes etc. to be much better in the 3D view because you can do it in...3D...and it doesn't need to be precise.
I mostly work in the 3D view at any rate, most brushes and dispalcements in my maps are clone dragged and rescaled copies of their neighbors, though precision lining up of detailed brush work and efffect entities like ropes, light glows, etc. is better in 2D view, I don't have any trouble with lining up world brushes in 3D so long as your grid is set high...