It really makes no difference whether the person was in the 4 or 5 year course. It's only down to the individual, how hard they've worked and prepared themselves. There's nothing covered in the 5 year course that isn't covered in the 4 year course, the 4 year course is more difficult because everything is condensed into a shorter time frame.
Not even to mention the fact that Graduate entry medics are GRADUATES, and will have had far more maturity, experience and knowledge than must undergrad medics. Graduates are more motivated and have clearer goals for themselves, having had already done a degree they will have a better ability to cope in a university setting.
Whoever told you that 4 year courses are somehow less superior are really sadly ignorant.
Are you forgetting the American medical school system which is basically GEM? There is no such thing as undergrad medicine in America and Canada. Medical school is always post graduate, after a first degree and it is only 4 years.
Considering that America happens to be superior in medicine, innovations, surgeries and medical schools, I think its safe to say Graduate medicine is just as good if not better than undergrad.