We’ve done both of those times, and we’re Pennsylvanian as well, so we may have some helpful perspectives.
We found the crowds and wait times in Feb somewhat lower than May, but both are fine. Temps for us in Feb were comfortable “light jacket” weather most of the time(The Floridians would not agree) I wouldn’t take alot of shorts or plan on water parks in Feb, but we did get into the resort pool a couple of times, even in Feb. If you’re in a moderate level hotel, they have hot tubs which were very popular, even in the cooler weather.
May actually got somewhat hot in the mid-afternoon, but was comfortable for most of the day. Our “northerner’s” skin may not be ready for the Florida sun at that time of year, so don’t forget sunscreen and hats. Lines were a bit longer, so we’d be at the park at rope drop, hit the “biggies” up until lunch. After lunch we’d go back to the hotel for awhile, or Downtown Disney, then hit the parks again when everyone starts to leave for dinner. Water parks are definitely “in” for the May planning.
I think it may be a personal preference kind of thing, but either time is good.
Hope we helped!