JVC DLA-RS20 vs. Sony VPL-HW10
No contest in price, no contest in performance. The Sony is far less expensive, but black levels are not even remotely in the same league. Other lower cost projectors that do notably better black levels than this Sony (Epson UB projectors for example), still don't come close to the RS20. The JVC has a real but not great advantage in placement flexibility, but that's only an issue if the Sony won't work in your room and the RS20 will, and that's probably not more than 10% of potential buyers, and easy to figure out.
The Sony VPL-VW70 projector is the official competition for the JVC DLA-RS20, but we haven't reviewed that one yet (March 09, most likely). The Sony is also not a match in terms of brightness. As regular readers know, our old gear measured lumens higher than most other reviewers - 30%+ higher in some cases. Our new gear is in line with everyone else (more accurate). The Sony measured 836 lumens in best mode (old gear) which we translate to 597 lumens, not drastically less bright, but still well below the 775 calibrated numbers for the RS20.
The HW10 is the lowest cost LCoS 1080p projector out there. If you like the fine pixel structure of LCoS, want to avoid rainbow effect from DLP's, it is a worthy projector, but it's not playing in the same league as the RS20.