Whereabouts in the Northeast are you and your wife from? I'm originally from Rhode Island and currently reside in Boca Raton. Yes, it is true that most of the transplants living in southeastern Florida and on the Atlantic Coast of the state are from the Northeast whereas most of the transplants living on the west coast are from the Midwest. Like a previous poster mentioned on this thread, that's most likely due to the fact that I-95 spans nearly the entire east coast of the state whereas I-75 spans the majority of the west coast of the state.
Believe it or not, I actually study demographics and demographic trends in my spare time. I know, I'm a nerd!
I've noticed that there are far more transplants from New England, Upstate New York, and western Pennsylvania living in the southwestern part of the state (Naples, Fort Myers, etc.) than in the southeastern part of the state (Miami, Fort Lauderdale, West Palm Beach, etc.). Most of the transplants from the Northeast living in South Florida are from New York City, Long Island, the Lower Hudson Valley, New Jersey, Southwestern Connecticut, Greater Philadelphia, and the Baltimore-Washington Corridor. Living in South Florida for two-and-a-half years, I can say with certainty that the aforementioned places are where the majority of South Florida transplants originated. I always tell others that the Gold Coast attracts folks primarily from the Mid-Atlantic. Transplants and retirees alike from New England, Upstate New York, and western Pennsylvania seem more drawn to Southwest Florida; most likely due to its slower pace of life and lower population density; than to South Florida which is very urban, very densely-populated, and is characterized by a very fast-paced lifestyle.
South Florida, north of Miami-Dade County, has a large Jewish/Italian-American presence and vibe whereas Southwest Florida has a much larger German/Irish-American vibe. For example, if you're a German-American from Buffalo, NY or an Irish-American from Springfield, MA; you may feel more comfortable or at home on the Gulf Coast than on the Atlantic Coast. But if you're a Jewish-American from Long Island, then you'd probably fit in much better and feel more comfortable in South Florida than in Southwest Florida.
Just an observation of mine...