Mixture, I learned in the US a few years ago, and I have to say that your description of what to expect in the US is not one that I recognise. "Sun-soaked blue sky" is a wrong assumption to make about Florida in summer. While low cloud was never an issue, the thunderstorms and heavy rain definitely were. Not enough to delay my training, but certainly for making go/no-go decisions or deciding which direction to go.
I learned at a very busy airfield when you could regularly have 6-10 aircraft in the circuit, without ATC so you quickly learn RT situational awareness. A busy international airport was a few miles away, and so learning RT confidence and brevity was important - ATC didn't have the time or patience for hesitation or unnecessarily long calls. There was a mixture of Class C and D airspace in the vicinity of the airfield, and a visit to Orlando is busier than what most (if not all) students will experience in the UK.
I did my JAR PPL (as it was then) in 3 weeks, including all written exams. For most days it was 2 or 3 one hour lessons and it didn't feel rushed at all. I even took a couple of days off in the middle of the course as I was progressing too quickly (time wise, not academically). The great thing for me was that everything was fresh in my mind, so I didn't need to spend the next lesson revisiting what I learned in the previous lesson. This made it less repetitive and more varied.
I would definitely recommend it. Just don't expect it to be a holiday or to go out and have a drink every night (a common mistake for some people who come back without a PPL).