Moat likely keeping iPad 2
Thought long and hard about selling iPad 2 and buying 3 but have come to the conclusion the only real noticeable difference between the two will be resolution, which isn't good enough a reason to upgrade because there aren't enough source material produced at a resolution for the device to take advantage of.
However, I will still await a few comparison videos before I will completely rule it out.
I really hope not too many people upgrade or buy the new iPad because if they do, Apple will buy into the herd mentality that whatever they come up with will make people buy their product and therefore each new iPad will have only subtle improvements rather than having drastic improvements. Or, if Apple cannot come up with drastic improvements,maybe they should introduce new each new iPad in a two year cycle.
You may wish to view the Apple intro video
There are lots and lots of improvements over the old, slow iPad2.