Projection screen: motorized or manual? (gain?)

[Tahoe Gator]

I plan to put a projector in my basement family room and thus need a projection screen. I plan to have a 42 flat screen on the wall for normal use, then drop the screen and use the projector for evening/movie watching, etc.

Any suggestions on manual versus motorized? I've found manual screens for about $150 and motorized for about $250, but the manual has a gain of 1.8 versus 1.0 for the motorized. Any suggestions on manual versus motorized, or thoughts on the importance of "gain" appreciated.

[AVMASTER]

gain isn't as critical as it used to be but you would still need uniform light distribution. I think a more important factor would be size and the type of material it should be constructed of. If its' motorized you need to determine how you would control it-wall switch,IR remote, etc.. and placement, i.e. in the ceiling or wall mounted