at one time had a no liveaboard rule
but I am not sure if it is still in effect. It certainly is not generally enforced as I met plenty of liveaboards when I was there.
FL will require you to get a state registration
if you stay longer than 90 days (same with most states) but the cost is minimal, generally $100-$200 max. There is a possible sales and use tax liability but if you are a non FL resident, have purchased and used the boat in your home state for at least 6 months then you will be exempt. Or if you paid sales tax in your home state when you purchased the boat you will be credited that if FL decides you are not exempt.
Otherwise, no state income
tax, no property tax on boats, nice weather
. Although in north FL we're looking at mid twenties in the morning I think that beats what you're getting in ME.
Generally the further north in Florida
the cheaper it will be although parts
of the Keys are much cheaper than Miami/Ft Lauderdale area.