Throughout this review, I've commented on how this Optoma compares with other 1080p projectors, and normally I do a lot of competitive commentary here. Since, however I plan to be publishing our 1080p comparison report, in about 3 weeks (or less), I'm just going to reiterate a few comments, and leave the rest for the Comparison Report.
1080p Projector Competition
DLP projectors have always been described as film-like - natural looking, and the Optoma HD803 is no exception. The choice, for example, between the HD803, and the Epson Home Cinema 1080 UB, in many ways is going to be a personal one. The Epson may do significantly better black levels, but has a slightly hard looking image, compared directly to the HD803. The Epson can also really crank out the lumens when needed, offering close to double that of the HD803, even though it's a tad less bright in best mode. Personally I didn't find that hardness to be an issue, even being the owner of the JVC RS1, definitely considered to be a very film-like projector. Interestingly, despite the slight brightness advantage in best mode of the Optoma, I found the Epson to handle larger screens better. This I tie to the Optoma's overall slightly darker look to images (but in fairness, it has richer dark color handling).
The Sony VW40 poses a greater challenge for the Optoma HD803. It's similar in film-like nature, although it has a different flavor to the image, and almost identical in brightness in "best" mode, although not as bright when you want maximum lumens (it's not that much less bright though). The Sony, like the Epson, wins hands down in placement flexibility, compared to the HD803, which being a typical DLP has only a 1.2:1 zoom (compared to 2:1 (Epson) and 1.8:1 (Sony VW40). Also, the other two have lens shift, making shelf mounting easy (the Optoma can't be shelf mounted except down low).
Between the Panasonic and the HD803, I just don't know. Black levels should be roughly comparable, and the Optoma appears sharper, but both provide really watchable images, though without gamma adjusted the Optoma will be noticeably darker. I've seen these, too far apart in time, to figure out which I would prefer. I'd really have to see them together, or at least close in time. Most people will buy the Panasonic though, because of its placement flexibility. The HD803, really needs to be ceiling mounted, and in addition, the significant lens offset puts it more than 1.5 feet above the top of the screen, which kills it for people doing basements that don't have standard ceilings.