I've lived in FL prior to here for 21 years, I never lived in Pcola though. We only had one hurricane hit 30 minutes N. of where we lived. (Out of the the hurricanes that threaten FL and it was category 4) And we barely got much damage, had power off for a week was the hard part but it was fun being off school/work because no power. Also usually if a hurricane is coming you always track it plenty of time in advance, so if you think it's going to hit your area you can evacuate and leave very quickly/easily. We never left. Even when one was projected to hit us, it didn't. It hit completely somewhere else.
No need to worry about gators. We had pets that would escape and a ditch in our far backyard and lakes on the golf course across the street, no incidents with any one's pets and the gators. If you see a gator in your yard, area, lake, etc you can call people and they will come and move it to a bigger lake, etc. I know many families who did this when they saw gator eyes in the lake as they had lil kids.
The weather is pretty nice in FL. North FL is nicer than southern. It usually rains a lot during the spring. It can get humid at times. Pensacola is near the beach so that's awesome! I love the gulf beaches! I prefer it to the pacific/Atlantic actually, it's calmer and more peaceful IMO.
The cost of living in FL isn't that bad, MUCH better than CA's prices. The houses are nice and reasonably cost, gas is cheaper that CA.
There's things to do: the beach, zoo, dog track, shopping, water park, arcade, a lot of museums, skydiving, sports, etc.
Some history on Pcola
http://www.10best.com/Pensacola/locationDetails.html seems it's a big Naval Air place.
Now for CA, I never lived in the mentioned/listed cities but I'm about 4 hours or so south of them. I like CA's scenery- the mountains are nice and weather is cool, but I dislike the fact things here are soooo expensive!! Take a 3bd/2br house here is basically 2-3 times more than almost anywhere else in the US. I particularly do not like where we're at as we are in a small city, there's nothing. I would probably prefer one of the cities you listed, but I can bet things there are probably a lil pricer? I'm not certain, but just a guess. Oh yea, I do know that San Fran is even MORE expensive than here. a 2/2 apartment in the city is like over 2G a month. Traffic can be bad at times on the freeways.
And for the UK. Not sure if you've ever been to the UK, but it's different that the US, a good different, there are some things that take a lot of getting used to. I'm sure Emma or Claire will share more

since I only lived there 3 weeks. The weather has it's up and downs. Mostly it rains a lot and it's usually pretty cool, so sometimes it can be a bit depressing if you don't see the sun for a few days or so. The driving on the other side of the car/road is something that took me a bit to get used to, almost got run over. Their washers and dryers are all in one, it does both which is pretty cool/smart. (at least this is how it was like where we lived) Traveling within Europe is cheap! You don't really need a car to live there, everyone usually takes the train, subway, bus or walks. The food there is good! The accents are awesome! The buildings are so neat and unAmerican
Hope this helped some April~ Good luck!