Since PESIT and PES University are both on the same campus, will there be any difference in the placement and education in the two? If so, then which will be better?

In terms of placements, there is no difference as such- whether you talk about PESIT or PES, both colleges provide good placements. 

The students of both universities get to sit together with each other inside the campus. Jobs depend upon how well you perform with your abilities. The better you put your abilities to use, the higher your chances of getting a job are. 

But if we consider education, there is a difference that is to be marked. If I talk about PES, this is a University entirely. On the other hand, PESIT falls under VTU which is the South Campus. Now, faculty-wise, both the colleges share a fine set of faculty that can inspire you in many ways. You can end up learning a lot from them.