The answer to this is quite complicated, depending on how you approach it.
Firstly, since PPE is a tripartite course, the tutors between each subject, even within the same college, can obviously vary. For example, Pembroke (the college I applied to) has a broad and high-quality set of Economics tutors which is also reflected in its generous Econ&Management intake and rep. So if you were a PPE'ist who favoured economics that may be one worth investigating. I'm sure there are equivalent colleges for Politics/Philosophy too, but I don't personally have great knowledge on this.
Secondly, I think there is a rather separate thing of a college's general academic ethos and work ethic. Some colleges are particularly renowned for pushing their students hard, for example Merton. Others meanwhile, are relatively far more relaxed in what they expect of students. It tends to be, of course, that the colleges that are more of a 'grinder' workwise produce more firsts. Depending on what type of a studier you are, you may find yourself happier at one type of college or the other. I point this out because if there is a college getting more firsts than any other in a certain subject that needn't neccessarily mean the tutors there are exceptional, but may simply mean its students are of a more hardcore-studying type.
Hopefully you will have a chance to visit Oxford before you apply, as simple first-hand exposure and your 'feel' for a college is I think a hugely important aspect of choice.