Can anyone share knowledge about the the most important technical specs or features of a digital projector that contribute to optimum image quality?

All I can say is I NEVER use an LCD projector on location without first building a profile for it using the GretagMacbeth (now X-Rite) I1 Beamer. It can make a huge difference in color and tone.

Andrew,
Any thoughts on the DLP technology?

From what I can find, DLP provides better contrast and color but may have some "flicker" when a small segment of people view it. The thinking is their eyes are more sensitive to this but it is not a problem for most people. I have seen DLP TV and it is really nice.

Thanks

My Optima H31 is DLP and I love it. The flicker I don't see. Very, very occasionally I'll see the white "rainbow" effect but more so on my Samsung 56" DLP HDTV.

I got the Optima Gray Wolf screen which really helps the contrast and blacks.