I just went through the same thing and ended up with a da-lite screen. I found that I learned the most after talking to the Manufactures and distrubertors.
I say give them a call and see what they reccomend. I am glad that I did.
I ordered a Matte White 120" cosmo electric last week to match my Panny 4000. The trouble is I have never seen either, so I am relying on this forum, Da-lite, and Projector People to steer me in the direction.
Both the screen and projector should be here next week and I will let you know my thoughts.
Thanks Rod. Both Da-Lite and Projector People thought that the Matte White screen would be best for my application. It seems that everyone is jumping on the HP bandwagon and for good reason its a great screen, but I feel that the Panasonic 4000u is too bright for the HP.