There are lots of reviews of the new iPad. Lots and lots. My review? In deeply abbreviated form, here it is:
The screen is amazing. You must see it before you make up your mind. It's pretty much every superlative people have thrown at it, aside from the glare and brightness all of these suffer from in direct sunlight. Everything else is nearly the same as the iPad 2, save slightly more weight and thickness, but if you're going from an iPad 1 to the new one (as I did), you won't be bothered a bit -- you're still saving weight and thickness over the first-gen.
Charging takes forever; it's a big mother of a battery in there, capacity-wise. 4G is flipping awesome, I watch my bandwidth like I used to count my minutes on