Most expensive does not necessarily mean the best. Go to the school that's got the best reputation for training. I would go to the school that provides the best training and not just a so called ' designer brand '. Teaching wise I've heard lots of negative opinions of Oxford more the American side of things so be wise and visit the schools , talk to their students and don't be fooled by marketing. I went to a very reasonably priced school and spent half what my colleagues doing the same job at the same company did.