A fatal mistake would be to chose a projector that could not fill your screen or one that does not have the installation flexibility and result would be a distorted image.
• Zoom range:
Make sure to use a projection calculator to check if the projector will fit in your installation. A 2.0:1 zoom factor will give twice as big a picture at its widest angle than its telescopic, and therefore more placement flexibility options. That is fine with many setups, but that does not mean avoiding a 1.2:1 lens projector. Just make the maths to figure out weather it works for your setup of not
LCDs are the most flexible in this regard.
• Lens shift:
lens shift allows to throw the image up and down, left and right which enables you to place the projector anywhere within the range of shift.
Same here, LCDs are more flexible, DLPs generally do not allow more than a bit vertical lens shift.
Make sure picture alignment is made through lens shift rather than Keystoning which will likely deteriorate resolution and soften the picture. And generally speaking avoid any lens shift at all if possible in order to minimize any plausible anomalies like uneven brightness and
Chromatic Aberration