We've stayed in a Boardwalk room and quite enjoyed it. It can get loud at night so if you go to bed early, it may not be for you. But we enjoyed people watching and seeing what was going on on the Boardwalk. I also liked the fact that you can see the water in the distance.
We have connecting Boardwalk rooms for our next cruise with our kids. Can't wait.
We have yet to try Central Park rooms. We did have it booked but didn't make it on the cruise. But when we are considering one over the other, I tend to lean to the Boardwalk rooms just for the fact that you can see the water...and seems more fun than Central Park (although I'm sure those are lovely and peaceful).
Both seem to have pros and cons.