Having done various courses both sides of the Atlantic, I'd venture that there are many good schools and instructors either side.
BUT, if you are going to primarily fly in the UK, then you need to learn how to fly in the UK. Go and do your licence in the USA by all means, but budget for time spent here with an instructor as well.
There is then much to be said for this route, learning to fly in the UK takes a very long time - largely as has been said down to the weather. So, doing a PPL in Florida in about 4 weeks, then spending a few weekends flying from your local club, with a UK instructor, isn't a bad option.
Echoing what IO540 said however, budget also for at least a couple of thousand a year for the first few years after getting your PPL - you need to at-least start by doing a reasonable amount of flying to consolidate it all. This is true whether you learn in the UK, US, South Africa, or for that matter Mars.
G