now that I've owned the jvc with lens memory, it's a feature I won't live without!
it's not perfect though, it tends to drift a couple pixels from time to time, but still, it's so convenient. even just having the motorized controls helps a ton, since you can stand at the screen while making adjustments. with my old manual Epson, I'd have to make SEVERAL trips between projector and screen to make sure everything was lined up. it wasn't that bad then, because I only had to do it once(and then repeat whenever I bumped into it...).
but yeah, the lens memory definitely opens up a lot of options, and makes them easy enough to actually use. I rehung an old screen and now have one white and one grey screen, and have presets for each. I'd never have bothered to do that without lens memory since it would be such a hassle without it. but now it's not a big deal, and even though the grey screen doesn't make a huge difference, it's as easy as changing source input, so I use it for viewing in ambient light
Displays: Samsung PN64F8500/JVC X35
AVR: Pioneer VSX-1130K, 7.1/5.1.2 audio
Sources: HTPC(Enby), PS3, XBOX360, Wii
Control: Harmony One