Hi...
My own (very personal view point) slant having been born in the UK, lived in Florida for 12 years and then here in NZ for 3 years now, is that there is really no fair comparision; it's like asking whats the difference between an apple and a fejoa or which has the better wood, or the best taste.... it cannot fairly be done (I feel).
What struck me about living in all three places is how each "country" and therefore the (majority) of folk, culture etc that live there resonated differently within me... I loved certain parts of Florida, I miss bits and aspects of the UK, I even miss having the access to parts of Europe, but it comes down to your prefered lifestyle choice(s), and what resonates clearly in you. What are you looking for?
You ask the question on here about whats it like to live/work/play/eat/travel in NZ and you'll get as many different answers as there are members I suspect!!...OK, maybe stating the obvious there, but it comes down to what you and your family feel and think. It's a hell of a move to come here as folk will (again) testify and gladly share their experiences with you.
I'm with the wise JandM
, if you can come here for a recce and a feel for NZ as a place, the trip will give you a sense of resonance and put "stuff" into prespective more.
What ever happens... good luck!