To elaborate on that somewhat unhelpful post - I don't believe that there's a single 'best at PPE' college. There will be excellent tutors at all colleges. I think it's perhaps more useful to ask, "Out of the colleges which offer PPE, which is the most [insert metric(s) of choice here: friendly, conveniently located, pretty etc.]?"
I can personally vouch that Brasenose is very friendly, conveniently located, and pretty. However, you should definitely go on college tours for ones you're considering and judge for yourself.