I did my PPL and IMC at KingAir at Biggin between 1997 and 1999. It's now been amalgamated with BHSF and is apparently more 'corporate Cabair' in its outlook. The guys there in my time were brilliant and I learnt tons from them. Even though they were hours building and many were on a scholarship themselves they were also dedicated teachers with a great attitude which started with the CFI and carried right through the school. I can't praise them enough. I know they've all moved onto different airlines where they deserve all the success they get.
Only had one bad experience with a school in Winter Haven, Florida. I don't even know whether they still exist, but it made me more determined to look very closely at hire outfits in the USA before committing to them!