....but ended up going with the HD20.
This is my first projector and I use it solely for watching movies; blu-ray, DVD, and streaming HD from VUDU\Netflix. I had nothing to compare it to except for my brothers which was a Optoma 1080p projector with a throw of 15-18 feet.
I was very impressed out of the box. Blu-ray looks great @ 11' throw\85" diag. picture. Works quite well in ambient light, but really comes alive in lights off. HD stuff looks really good from viewing distance of 12'.
There is some rainbow effect, but not often at all and usually during credits. Certainly not a deal breaker for me. We watch it directly off our light gray painted wall and it looks very good. Older DVD's are blurry, but that is just the nature of the lower res DVDs. The texture of the wall and no gain gray paint will require a screen eventually.
The controls are pretty basic and simple to use. There are some advanced calibration settings that I didn't mess with.
Overall this was a very satisfying experience for the money.
However....
I felt that the 11' throw\12' viewing distance put me right on the cusp of being able to benefit from 1080p. I got the bug and started obsessing about it and decided to order and HD20 to compare it to, realizing I may take a restocking hit on the returned projector. I really wanted to see the difference because I felt that at 85" to 95" inch diagonal I could really make the hd stuff crisp.
Set up the HD20 yesterday. First run was in soft ambient daylit room with shades drawn. I immediately noticed the difference in brightness. The HD20 at 1700L vs. HD66 2500L was definitely not a good viewing experience in ambient light. Even on bright mode, the picture seemed washed out. I became somewhat discouraged, but since my gf and I pretty much only watch with lights off at night, no cable, I waited to make my decision. Fan noise a little louder on HD20 especially on bright mode.
Once it became dark outside, the experience totally changed, even with low light in the room, the image began to get brighter and clearer. I watch several HD previews off of VUDU and Up in standard DVD and Avatar on DVD.
Verdict, The HD20 really made a difference in 1080P. It just seemed more comfortable displaying it's native res than the HD66. From my viewing distance it was really really awesome. My girlfriend came home, I didn't tell her I swapped them out, and she immediately said, "Is there a screen there, the image seems really sharp." I chuckled and said no.
Final Thoughts:
If you are throwing from 12" or less and viewing from around 10' to 12' AND you want viewing in ambient light AND your budget is limited, The HD66 is a great buy. You won't be disappointed. If however, you can spend the money and you are throwing from farther than 11' AND you will be watching primarily in dark or near dark room, I would say go for the HD20. I was a bit nervous until I put UP in standard DVD in and it looked better than in the theater. It was really crisp and that was without a screen(which does help a lot, I tried the HD66 out with one.)