I also trained at UKFT but for me it was an excellent course and I learned loads, completed on schedule and up to standard, and seemed to experience every hazard imaginable - it very much depends on your instructor, and your ability and attitude. Some of the other people there with me were having a fustrating time achieving PPLs, in terms of needing loads of extra hours and repeatedly re-taking exams and even the skill test, but frankly that's cos they couldn't learn to fly or navigate or whatever very fast and of course for some people this has to be someone else's fault.
Hidden charges: nothing I can recall, just watch that if you log more flight hours than the minimum or have to retake the skill test or exam then the final bill will obviously reflect that. The $15 student accommodation is a bit sparten, the guesthouse motel is much better.
Finally a lot of people seem to be rubbed up the wrong way by the owner/examiner, but having since experienced several other outfits I can report that there are many far less agreeable FTOs, where you also get rubbish tuition and unexpectedly shocking invoices (and not all in the US!).