What are the differences with on/off contrast?
I know with at least JVCs, you can use vertical shift to increase your ANSI contrast.
You realize that you are comparing a current Sony to an older superceded JVC right? IF you bought a recent RS10/20 just a couple of months ago from AVS, trust me it would have been a steal. I am talking about about a solid 60% less in price than your link says.
JVC is on their third gen of this pro series, and by the time you buy, they will be on their fourth. From what I have read, I think JVC gets the edge in both reliability and value, at least going by street pricing. I know that strube here will never ever buy a Sony PJ again, but those are older, lesser models. However, some Sony's are indeed comparing favorably, if only at a glance by myself. I will myself only consider JVC for the foreseeable future, as far as I can tell.