The thing about the iPad's new retina screen and processor is that yes, they're nice, but it's up to developers to take full advantage of it. Here's how some of the better retina iPad apps compare to their iPad 2 equivalents.
We played Infinity Blade 2 and RealRacing2HD, both of which were updated for the new retina display. For RealRacer, there was a noticeable difference in the textures, but the animations were the same. Because of the way your eyes work in a racing game, it was pretty hard to tell.
For Infinity Blade 2, though, the lighting and environment detail was noticeable from the start, and the in-combat graphics looked much, much crisper and more fluid. The character models especially looked better on the new iPad during combat.
Oddly, neither showed much improvement in load times with the new processor, and there wasn't much difference for in-game performance either. It's pretty clear, though, that once games are developed specifically for the new iPad, they'll get a lot prettier in a hurry.
We tested the ABC Player, Netflix, and NCAA March Madness Live apps. The ABC and Netflix players compared out about the same across the two iPads. Video quality was more or less equivalent, with the iPad 2 falling behind only occasionally. But while the new iPad's screen comes off as "warmer" (almost yellowish) in text-based apps like the NYT, it was just plain brighter with video streaming.
The NCAA app, for whatever reason, was much cleaner on the new iPad. Lines that were blurred and sections of the crowd that were mushed together on the iPad 2 came out with much more detail on the new iPad. There was much more discernable detail in the closeups between the plays, but that's the case with sports in general.
For most apps, though, you're looking at a linear upgrade. Evernote, Twitter, Tweetbot, Wordpress. They're basically just a direct port of the previous version of the app, with a sharper interface and sharper text. For the most part, the retina display wasn't a very big deal for text-heavy apps, and load times were nearly identical between the two iPads. There are, though, a few exceptions.
The first two are the New York Times app and Flipboard. The way both apps are laid out, with smart use of space and integration of visuals, completely plays to the strengths of the higher res screen, and both look great.
The other is the Comixology-powered Marvel Comics app. The new HD books look incredible on the retina screen—better than a print book, with basically no need to expand the panels. The text in the captions and word balloons is all totally, perfectly legible without straining your eyes, which is a big step for digital comics.
So does the retina display make a difference? If you're a heavy iPad gamer, definitely. If you watch a lot of video, somewhat. But if you mostly ready and browse, you're not going to notice an appreciable difference.