In this months MD, Lewllyn answered a question about the difference between test E,C,P and Sus. His answer was nothing. He said it is all the same and that marketing is behind the different types. From your personal experience has this been the case?
Of course to truly answer this the different tests would have to have been purchased from the same lab. You can't say that Test E from Lab YY was shit but you took Test P from LAB XX and it was amazing because then you cross over into manufactuers being different.