I have read (perused) a bunch of iPad reviews. The best are Walt Mossberg’s WSJ (Mossberg is the WSJ Personal Technology editor) and David Pogue’s New York Times review (Pogue did the Missing Manual series for the iPhone).
My take is I really like the enhanced resolution, I notice the weight increase, but I have not yet felt the increased speed of the new processor. Since I can tether with the iPhone, the 4G modem did not really grab me in the end. And according to the reviews, 4G networks are few and far between, but the data plan charges extra regardless, so I bought the Wifi only model.
I had a reason to upgrade, but otherwise I could not recommend it. If you don’t have an iPad and want one, then it’s certainly worth buying. Beware the naming confusion. Refusing to christen it as “3” makes it a little more difficult to order it and accessories online.