There seem to be five significant changes between the older RS1, and the JVC RS2
First: Contrast has been increased from a claimed: 15,000:1 to 30,000:1.
Although I couldn't compare them side by side, black levels appeared improved from the RS1, which already had, what most have considered to be, the best black level performance of any under $10,000 projector.
Second: The JVC DLA-RS2 directly supports an optional anamorphic lens for true Cinemascope 2.35:1. The RS1 did not, so to add their optional Panamorph anamorphic lens required a separate, outboard processor. Not so the RS2, all you need is the projector, and the lens.
Third: More control of the image has been added to the menus, although the JVC, in this regard is still no match for any number of other 1080p projectors, that have very sophisticated CMS (color management systems).
Fourth: The JVC DLA-RS2's HDMI inputs support HDMI 1.3b standards, including deep color. In the long run, that's a real plus, but it also means that you'll want the very best HDMI 1.3 cables if you are running more than, say 20 feet.
Fifth: The JVC RS2's zoom lens is now motorized for zoom and focus, whereas the RS1 had a manual zoom lens. Lens shift appears to still be manual, the literature doesn't specify, and I hadn't asked.
The JVC DLA-RS2 should ship as soon as November, but, as is usual, you can never predict which projectors will actually ship on time (most don't).
No final pricing, but it is expected to be about $6000 and change, similar to the original price of the RS1.
I should be about the first to get the JVC RS2 in for review, so I will update the site when I have a better idea of its arrival.