We were there last March break. It was busy - lots of crowds. If you maximize your Fast Passes and try not to stress out, you should be fine. For us, we knew that we would be back at the World 4 months later, so if there were things that we didn't get to do we didn't worry about it. It was also pretty cool there last March break, as they had a cold front move in.
Remember you are at Disney, what else could be better?