I saw the PB6200 at the parade of homes last year, they were playing The Two Towers on it. It shot a pretty good picture, but I would go with the Dell before the BenQ. 1. it's several hundred dollars cheaper and 2, it has better specs on it. (better contrast and higher lumens). We had the X1 at my old office and it was nice too, never seen the X2.
I got the material off of ebay, just do a search for "projector screen" and there are pages of them, depending on the size you want. The screen I made is 112 inches