The new screen is outstanding but you do need high res material to take advantage of it (images, not text)
Luckily, I read comics which come scanned at higher resolutions most of the time (recently at least!).
Hard to describe the difference so I took some screenshots and cropped them to try and give an example of the difference.
Spoilered all the images and explanation below: nothing is NWS
so...

vs

The screen is really really nice but at the same time, the iPad 2's screen isn't horrible so you notice it when doing things that I like to do...like read comics and pdf magazines that are scanned at higher resolutions that the iPad 2 screen. You can actually read the small text on a magazine page in portrait without struggling to make out the words like you sometimes will with the iPad 2 (or any other pad)
As for the claimed improved (44%) color saturation, I noticed it right away while viewing the same pages of comics side by side in iPad2/new iPad. Who knows if it's 44% but you notice it so it matters.
If you have an iPad 2, you may decide not to upgrade. It's not the end of the world, but everything looks razor sharp on the new screen. Eventually, you're going to want that...the same as you'd enjoy better shocks on your car, or a quieter cabin during your drive. These aren't needs. They are wants, but they are clearly better and the quality of the screen is huge on a primarily consumption device.
For me, after getting the new iPad, I picked up my iPad 2 and thought I wouldn't have any issue if I had to use that...but then I switch back the the new iPad and there's no doubt which one you'd walk out the door with if you were told to pick.
I'm a huge fan of Zite, which is a new aggregator app on the iPad. I'm holding the iPad2/new iPad side by side and the retina display looks perfect...now I see the dots on the iPad 2 screen. It really does make the old screen appear fuzzy. I've got to admit though, Flipboard looks really good and runs smooth on the new Pad.
If you're happy with your iPad 2, wait until you're ready. If you're in the market for a tablet, don't even think of getting an iPad 2 (or any other tablet out there). The new screen blows everything away.
Not to mention it destroys the latest Tegra 3 chip in that fancy Transformer thing in graphics and its two cores match or best the tegra 3's 4 cores in processing power:
http://youtu.be/4jdbtiNnZzE?hd=1
Hmm, usually the anti Apple people can boast about how much more powerful their device is compared to the overpriced Apple item...hmmm, what now?
New iPad is already jailbroken (untethered) for those that might complain about not being able to do something in that scary "walled garden".
http://www.geek.com/articles/apple/new- ... -20120316/
Oh, I haven't really played around much on the new iPad yet but the speaker sounds the best yet (of the three iPad generations). Loud and clear. It's not meant for music but for watching Netflix, listening to a podcast, youtube, etc, it's solid. There's no "flashlight" bleeding on the new screen either. If there's a dead pixel, I wouldn't know.