newer planes, better availability,
Not necessarily. I did my PPL in an old PA-28 because I did not like the even older C152. As long as the wings don't fall off, no problem at all. They are checked every 50 yours, engines are changed every 1200 hours and so forth. Flight training is a very marginal business and there's not a lot of money left over for new planes. Plus, there are still plenty good 2nd hand training workhorses such as PA28s, C152s and C172s available in the market so that schools don't have to buy new planes.
In fact, the most common training aircraft in the US is probably the C150/152 and the last one of those rolled off the production line in 1985 or so.
And as for better availability: every school will (should) have sufficient, but not plenty airplanes for the number of students they attract. So availability in Florida is not necessarily better, on average. The advantage of a relatively big school, with lots of students and lots of planes is that one plane going tech has less of an impact on operations compared to a small school.
The one single advantage (other than price, weather and so on) of training in Florida, what I found, is that they are setup for full-time students. So they employ full-time instructors, have in-house maintenance and everything, all setup so that you can complete your training in the minimum amount of time, with minimal delay. Schools that mostly or only have part-time (one lesson a week) students typically do not have the mindset and the procedures in place to get you through the course in three weeks.
Oh, and you did read this one, didn't you:
http://www.pprune.org/private-flying...-part-1-a.html