Yes the screen is obviously improved, much sharper and certainly easier to read text, but possibly not like WOW... i've gotta buy this, on films its not a massive improvement, buy very noticable on text AIS.
One of the things I was pleased to note, was how much faster web pages loaded compared to my iPad 1 (my wife now uses this) when comparing the 2 models, the iPad3 had loaded the page while the progress bar in Safari was only halfway across on the iPad1, so that really was nice to see, though it's possible that the iPad2 already has faster web browsing than the iPad1 anyway. I also think the sound is better that my Ipad1, but again the iPad2 has similar design to the new one so that may well be the same too.
So I suppose it's really down to the screen, as other differences would not be so great if moving up from an iPad2. In my case I wanted a second iPad so my wife could have my iPad 1 64/3g model, which sorta gave me the reason I needed to buy the 3, plus being a pensioner, I likely have more money than sense..lol.
Personally, if one has a iPad2 and it does the job, I don't think I'd be rushing to get the iPad3, unless you have a genuine reason or can get a decent price for your iPad2, and most importantly of course, without it impacting one's finances too much. When I was queueing last Friday for mine, I was surprised how many young people were buying their iPads on easy payment finance, but thats their choice of course. I'm 68 so I suppose if one doesn't have any money at my age, your'll likely never have any..lol