I was able to see the HD81 at CES last weekend and was very impressed. It was one of my personal best-of-show products. I was particularly impressed at the light output on such a large screen which allowed the PJ to overcome noticeable light bleed in the lower right corner even on moderately bright scenes. This thing should be excellent for larger screen installations where the lens shift and throw are not showstoppers. Of course, it's not certain how well this brightness will hold up after calibration.
For the record I have the 60" Sony RP SXRD and felt that the overall smoothness of the image from the HD81 was competitive with what I see at home, which is something that I could never say about the 1080p DLP RPs (the wobulated ones). The resolution actually appeared to be higher than my Sony despite the equivalent panel resolutions, likely due to better optics, slight misconvergence of the 3 panels on the Sony, or simply better source material. While shadow detail appeared to be similar to my SXRD, I was unable to evaluate the last little iota due to the aforementioned light bleed.
I wish I could have compared the HD81 with the Ruby but Sony seemed to prefer pushing products that no consumer can currently or would ever buy (PS3, Blu-ray, and 4k digital cinema projectors). I understand the desire to build excitement for new things, but to basically ignore significant chunks of your available product line....?
IMO Panasonic killed Sony in this regard. But that's a rant for another thread...
FWIW, I also really liked the BigVizion 1080p 100" display out front. I think that's a great solution for (deep-pocketed) people who want that size screen but don't want to watch TV in a cave. It pretty much needs to be recessed into custom cabinetry, but at the price point they're talking about, most people will be building custom cabinets anyway. From what I saw it was the best way to get a 100" high quality image in a non-light-controlled room (better than black screen, 100+" plasmas, or an RP setup using a recessed short-throw FP). Panny's 103" plasma prototype was amazing for it's size, but when can you buy one and how much are you going to pay (and likely get lower contrast)? I don't know how large the market for BigVizion is, but it's something of a singular product (as far as I know). I do think that the cost will need to fall quite a bit ultimately to get any level of significant volume (probably to ~$10k for the 100") but for now Optoma can reap the rewards of being the only game in town. I wouldn't be surprised to see someone else follow Optoma's lead here. Infocus already tried something similar in RPTVs so they have the technical competence.
Sorry to go a little OT there at the end but I guess it is somewhat related.
Anyway, just my $0.02.