I don't know what the intersection looks like between gadget nerds and comic book nerds, but based on how many questions we've gotten about how legible and enjoyable comics are on the new Retina iPad mini, I'm guessing it's pretty large. Now the iPad Air, thanks to its large, 9.7-inch 2048x1536 display, is currently undisputed king of the comic book tablets. The Retina iPad mini, while including just as many pixels, crams them down into a 7.9-inch display. The difference is 264ppi for the Air, and 326ppi for the mini. Meaning, word bubbles are condensed smaller, lettering is condensed smaller - everything is condensed smaller. But is it too small?
Here's what a comic book looks like in iBooks, in landscape (top) and portrait (bottom), at 326ppi on the Retina iPad mini (left) compared to 264ppi on the iPad Air (middle), with the iPhone - also 326ppi but with a much smaller 4-inch display - thrown in for good measure.
Obviously, reading a single page at a time in portrait orientation offers the biggest, best experience. It's roughly equivalent to reading in landscape orientation on the iPad Air. A double page spread in landscape isn't that far behind, experience wise. The Retina screen makes for crisp letters and lines, and gorgeous colors. (Yes, Superman's bright red cape looks just fine, thanks.) My eyesight is terrible, and I can read them perfectly well in both orientations. In fact, I generally read in landscape, even on the iPad mini. I've been doing that exclusively for the last week and I've had zero problems.
I do prefer comics on the iPad Air, because it's closer to actual comic book size, but the Retina iPad mini is far more portable. If that sounds like the same tradeoff as always - portability vs. screen size - it's because that's just exactly what it is.
So, if you want full-sized art, and you'll be reading at home, the iPad Air can't be beat. If you simply want all your comics with you all the time, even and especially when you're traveling, then the Retina iPad mini is not only a fine alternative, it's a fantastic one.