I bought a Qumi and got it on friday. Here are my pros and cons:
Does have to be refocused upon turning on and then after it warms up as focus will drift after it heats up.
It is bright enough for my 92" 2.4 HP screen
Can't see the pixel structure unless very very close to screen
Quiet.....really surprised me how quiet it is
Colors look great....especially blue
For $500 I am impressed. Sure having to refocus after warmup is a hassle but the projector is so small you should expect it. This is a great projector to just watch TV, play video games, or use as a backyard small theater. I will use it to save hours on my bulb projector and being able to turn on/off as much as I want doesnt hurt either. The 500 lumen projectors should really be something if they are like the qumi but brighter.
JVC RS600(Calibrated with Chromapure using an iD3), Stewart Cima Neve 2.35 115" diagonal screen, Lumagen Radiance XD, Darbee Darblet, Denon AVR-X7200WA(7.6.4), M&K Speakers, 6 ported 18" subs powered by 3 inuke 6000dsps, Oppo BDP-93, Roku 4, Samsung UBD-K8500 UHD blu-ray player