After 2 years with the RS55 I have 1395 hours on the original lamp. Viewing has been mostly in Normal (low-lamp) with the occasional 3D viewing in high.
106" Da-Lite 1.1 gain
Dark-brown walls, carpet, and couch
3D was getting pretty dim, even at iris 0, and 2D seemed OK at iris 6 (instead of 12 when the RS55 was new).
I just installed a new lamp (PK-L2210U) from AV Science and wow! Everything about the image is much more "full." It really does seem like getting a new projector. Transformers: Age of Extinction in 2D looks dynamite. It looked good a few days ago on the old lamp, but now it's even more dynamic in bright or dark scenes. The outdoor scenes in the sun at Marky Mark's farm were a revelation. The sunlight on them is so much more realistic, and it shows just how dim the old lamp had become.
Over the last few months, I was on a User 1 setting by eye, with a gamma of 2.0 to bring out shadow detail that THX was crushing. With the new lamp, THX looks like a better combo of blacker blacks with "enough" detail. I know, a calibration would do wonders, and I'm finally looking into it.
Because I am another upgrade-insane AVS'er, I'm also testing the friends and family network to see if anyone wants to buy an RS55 with a new lamp so I can get the RS4910
In any case, the moral of the story is that a new lamp can do wonders.
QUESTION: I'm almost out of the 2-year warranty on this refurbished RS55, and there is a fair amount of dust visible inside the back-right vent. Has anyone ever sent their unit voluntarily (!) to Mendtronix for a cleaning? I know it's not covered, but it would be nice to get a clean unit after 2 years of dust intake. I clean the removable screen every 2 months.
Thanks to everyone else on this forum who contributed their experiences and observations!