It's the first time I've felt the need to post on this forum, because your post struck a chord. Myself (UKC) and boyfriend (USC) have just come back from a visit to the UK where we told my family and friends were are planning to move from Boston to the UK in early 2012. We were met by incredulity from some, even some family members. It is a little disheartening, especially since it has not been a straightforward or obvious decision for us. But heads started nodding when we explained our reasons, and although their initial reaction wasn't exactly encouraging, I'm not going to let that change my mind.
I'm going to generalize here, but British people do not have the same patriotism and love for their country as Americans, and the negativity can be frustrating. It seems to come in all flavors: taxes, wealth, health care and weather. Ever since I can remember, people have said things like "this country is going downhill". I wonder if it's something to do with the media always portraying aspects of the country in a bad light.
British people see Florida as a holiday destination, so in a way it's natural for them to think you would want to live there - after all it's somewhere they would pay money to go. However, you have to remember that for many Brits, a holiday destination is all about hot weather and beaches, it's almost like it's been instilled in them from birth that hot is best. I remember that when I was growing up I wondered if something was wrong with me because I didn't love hot weather as much as everyone else. Sure, I like it if I'm on holiday and on the beach, but not so much when I'm cycling to work!
Anyway, as long as you can get past the questioning, it really doesn't matter what their opinion is. You and your husband have obviously gone through all the pros and cons, and you're the ones who actually have experienced them and know what they are!