My rMini is the 128gb Cellular version. All 4 have had no dust and no dead pixels.
I finally have a nice screen, still has slight image retention, but this disappears far faster than the last screen. 2hrs gaming on GTA San Andreas on my first and second iPad had no image retention but had very bad backlight leakage and 30% of the bottom was yellow, top pure white.
3rd rMini had a pretty uniform screen but the 2hrs gaming on GTA San Andreas caused severe image retention, this took around 30hrs to fully disappear. The 4th rMini takes around 1hr, this is only visible on a dark grey background anyway so that's fine as it's far less visible than the 3rd one was.
This was the previous 3rd rMini, I loaded this grey image straight after 2hrs gaming.
After 12hrs you could still make out the on screen controls.
Here was my first rMini, the room was lit up with a 40w desk lamp, rMini was on roughly 30% brightness.
Looks a little worse than in person as the phone used took at it 1600 iso (5s)
Here is the current 4th rMini,
Backlight on 100%, this time in the dark, in person there is zero backlight bleeding, due to the high 2500 iso you can see patches, but in person it's pure black.
All white screen (100%).
3 different angles with the split keyboard. Looks whiter in person.
This gives a better idea of what the black looks like at 100% in the dark, you can see around the border there is no leakage at all. I am very happy with this iPad.
There are good ones out there. Shame the quality control is so bad, then again what quality control.