My experience is: Trained to BCPL/AFI and instructed in the UK, built hours in the USA, now instructing in Australia. Sadly I have to agree that those who have trained in the USA on the whole seem to have different standards than those who have trained in the UK. I recently had to almost completely retrain from scratch one guy who wanted to convert his USA PPL to Australian.
Having flown there I think an issue in the USA is that it is all so nice and user friendly, getting the weather, notams etc is all a breeze, ATC are wonderful and helpful and SOOOO polite. Perhaps it makes the pilots a wee bit complacent. Here in Aus we have to get all that information for ourselves, and in WA there aint no radar apart from the immediate vicinity of Perth. (Abovementioned chap was some 250 nm from Perth, and asked for a radar vector...) I think a lot of the descision making is too easy there, they don't have to think for themselves as much, and when they go to fly elsewhere it is overwhelming. It doesn't matter how busy the airspace or how big the other aircraft where you are learning by the way. Aviate and Navigate come before Communicate.
Re the JAA situation, I have asked if I can train for the JAA PPL here in Aus and have been told no, the training can only be done in member states. I asked if that meant the USA schools wouldn't be able to do the training and was told that was correct.
IMHO that's a good thing, because there is no such thing as "cheap" flying and too many wannabees get hurt by some of the sharks operating out there now.
------------------