Go to the US definitely - all in, with flights and accomodation worked out a lot cheaper than the UK, plus you get the continuity of training due to the fantastic weather. I can only comment on the schools I've been to in Florida - two friends of mine did their PPLs at Naples Air Center (they organise discount accomodation which helps) - very friendly, efficient, and professional with reliable aircraft but not rock bottom cheapest. I also know of Ambassador Aviation (also at Naples - similar setup). I think the cheapest I've heard of is Ormond Beach in Florida - bit of a sausage machine by all accounts, and aircraft not great, but they get you the piece of paper you need. One other bit of advice - do the groundschool before you head out and get the exams out of the way so you can concentrate on the flying, then it should be a breeze in 3wks.