Those of you comparing your new rMini side by side with other Minis, Airs, Androids etc: Make sure you are doing Apples to Apples (so to speak...)
1. Use a nice photo - something bright and colorful with a full range of colors and tones, dark to light.
2. Obviously use that exact same photo file (same res., etc) for all comparing devices.
3. Observe both under identical lighting conditions. If you are in a sunlit room, avoid any areas with direct sunlight that will skew lighting according to proximity to a sunny window. If you are indoors and it is evening, you need a room with completely even lighting. Maybe a smallish bathroom (or similar) that has CFL lighting. Expect confused looks when you walk into a WC with several iPads tucked under your arm.
4. Turn on the iPads for at least a minute to let all phosphors warm up.
5. This is the most CRITICAL part - Brightness is EVERYTHING. All iPads must have equal brightness. Assume no iPads are created equal, even if you are comparing two rMinis. Unfortunately, this is not an easy thing to equalize. The best way is to have access to a camera with a spot meter. Set the iPad screen to uniform gray, aim the camera screen center at identical distances and adjust one or the other iPad's brightness setting to get a match with the other, trying to keep it as bright as possible.
This is the only way, anything else is conjecture. Once setup, look at one iPad, close your eyes briefly, then look at the other. Close your eyes again and look at both. You might have someone come it and switch the position of the two iPads randomly to see if you get constant results. Then invite some "fresh eyes" to see if they concur.
I'm a professional photographer who has spent countless thousands of hours color timing images with Lightroom and Photoshop. I have also worked on visual effects in film production (a rather well known facility that was/is an industry leader). Comparing two iPads, two photographs or two 35mm film frames that have identical images absolutely requires a bit of care to get accurate results.