I've reluctantly joined the rs-56 club... I say "reluctantly" because I was happy as a pig in s*** with my 4+ year old rs-20 until, at around 3000 hours, it developed the dreaded pink-line issue. I had hoped to keep the rs-20 until something radically new and improved came along (led/laser light source, etc.). But as this pink beast was slightly growing week by week I could no longer live with the zoom needed to hide it so I decided to replace it. At about the same cost as the rs-20 the new rs-56 is in the house (thanks to AVS). So far so good... convergence is nearly spot on (slight fringing up close) and uniformity is good (not perfect) but at least as good as the rs-20. IMO, the black level is about the same and, of course, it is a bit brighter so I assume the contrast is better
. I'm using low lamp with about -10 on the iris projecting onto a 120" diagonal 2:35 screen (96" diagonal 16x9) with a panamorph 480 lens and transport.
The only place a step backward was taken with the rs-56 versus the rs-20 is the loudness of the unit... As I always use the "high-altitude" mode (Denver metro area) the rs-56 is quite a bit louder than the rs-20 was in this mode.
I don't think I'll have much use for the 4k feature... IMO it doesn't bring much to the table so I am leaving it off... much happier with what the Darbee does to the picture. Did a quick calibration using chromapure (along with our lumagen radiance XS... grey/gamma by hand with a 125 pt auto color) and a pro calibrated D3 and it didn't need much tweeking at all (grey/gamma were very close and only a very few of the 125 colors were out of the 1.75 dE range). Will do a more thorough calibration once 150+ hours are on the lamp.
Haven't tried 3D yet... heck I don't even have a 3D compliant bluray player (oppo 83) but given I really couldn't care less about it I doubt I'll splurge to pick up the equipment necessary to try it.