Seahound, I moved from Sterling, VA to Broward County, FL (Fort Lauderdale basically) over a year ago and it's been wonderful!!
If you are coming from Northern Virginia you will find hardly ANY negatives.
The positives:
Traffic: WAY less traffic down here compared to northern VA and DC. People actually complain about traffic in the Broward/Miami-Dade area. If people here have to slow down to 40 mph, it's "traffic"
I drive to work down 95 (yay express lanes) at 8 am and hit NO traffic, none! I would never attempt that in VA. I used to commute from VA to DC everyday and left my house at 5:15 am to avoid the traffic. If I waited until 6 am, I would always hit the congestion.
Cost of Living: Way less here for almost everything, especially housing.
People: I've found that people here are far more friendly than Northern VA.
Activities: There is soooo much more to do here. Obviously you have the diving, huge plus. There are also all sorts of water activities (beach, sailing, catamarans, kayaking, snorkeling, etc etc). They also have almost everything you could do in VA including the theater, concerts, camping, etc.
Weather: Wonderful. The summer can get hot, but you're from VA...you KNOW it gets hot as balls there too, and just as humid. The winters are beatiful and you can do outdoor stuff (like biking, hiking, jogging, etc) all winter long.
Travel: FL is a perfect gateway to Caribbean travel. You can fly to many of the islands for less than $100. Cruising is also a super CHEAP way to travel and brings you to some great diving spots. I just took my 7th cruise and it was only $300 (including lodging, food, taxes, port fees, gratutities, everything except alcohol) for three nights.
The bad stuff you hear that is crap:
Crime: I've lived here for a year and haven't been the victim of any crime. People talk about Miami's bad crime rate...well compare it to DC, DC is worse hands down, every time. Plus you're looking at Fort Lauderdale, so don't let the Miami crime chicken littles scare you.
Traffic: See above
Heat: See above
No one speaks English: This is another thing that I haven't encountered in Broward. In Miami yes, there are lots of areas were people speak Spanish. However, I actually don't find it any worse than areas of Fairfax, VA. Plus unlike VA, at least in South FL it's only a few cultures that you encounter. If you pick up a few phrases in Spanish you can get around in Miami, you don't really need any Spanish to get around Broward. I found in Northern VA I had to know Spanish, Korean, Chinese, Arabic, and about 5 other languages to talk to everyone.
If you are coming from central or southern Virginia though, then you probably will see more traffic than you are used to, and may not find that the cost of living is any better.
True Negatives I've found:
Drivers: The drivers here are the worst I've ever seen in the U.S. It sucks, you get used to it though.
Grocery Stores: I was very spoiled by the great selection of grocery stores in Northern VA - Wegmans and Harris Teeter being my favorites, then we had Giant, Safeway, Bloom, Shoppers, Whole Foods, and Trader Joe's. Down here you have Publix (the "good" one, I guess), Winn Dixie (ghetto), and Whole Foods. That's it :depressed: