The Optoma ML500 shows in stock now at provantage. I was about to pull the trigger when I noticed that it does NOT have an audio output. This is a deal-breaker for me, as I need the option to feed audio from media files and HDMI source to better external speakers.
The Viewsonic also does NOT have audio output connector.
However, the Acer K330 does, so is of great interest to me. I have owned other Acer products and found them to be reliable and support is reasonable. The translated Chinese test data cited above looks decent to me for a portable/compact projector. The center-to-edge light dropoff appears to be about 30% (others feel free to correct me if I am wrong)...many zoom lenses for cameras costing this much have that much vignetting in many spots of the zoom and aperture range. I am not sure that the others will be any better (?). In any case, I will wait for widespread availability and some reviews for the USA model.