Will my results differ when using a sourdough starter vs poolish for pizza dough?
Three things:


Most traditional Neapolitan pizza dough does not use a pre-ferment - poolish, biga, or sourdough starter.  Not to say it may not be good, but it wouldn't the way most are made.
Sourdough starters change their flavor profiles by age and by geographical region.  In general, I would expect a bit more of a 'tang' from the sourdough starter than from the poolish.
Sourdough starters usually don't rise as much - commercial yeast is just in general stronger than its wild counterparts.  So a dough made with a sourdough starter may not rise as well.


Between the two, I would prefer poolish over sourdough for a more traditional taste.  However, I'd be more likely to try something like a cold starter and super slow rise like a Pain à l'Ancienne in order to promote more natural sugars in the bread which would result in better browning.  The primary challenge with Neapolitan pizza dough is the lack of heat in a home oven.  Part of the thing that heat does is the browning - hence the recipe that promotes better browning but with traditional ingredients.