Deanofs:
It can play out in two ways...either you're getting lots
of different inputs from many pilots and so will have a
broader experience at the end of your training...or
that you are getting inconsistent and confusing
messages from different instructors.
If they are actively disagreeing then complain to the
CFI.
I think that it is best to try to only have one instructor
for maybe the first twenty hours or so but after that
having fresh ones will add a variety of viewpoints.
In practise though, more instructors does mean more
hours learning (IMHO).
-- Andrew