What is the difference in taste between kosher dill pickles and polish dill pickles? Do they have any visual distinctions that would make it possible to differentiate between them on sight?
Those are two different processes. Unfortunately English language don't have two words for the outcome and they are both called "pickles".
Usually Polish pickles "kiszony" should be made with:
cucumbers, dill, fresh horseradish, garlic and salt. No vinegar.
Kosher pickles, called in polish "korniszony", are made with brine that contain vinegar.
I assume that those two recipes have been mixed outside Poland and both things are "korniszony" with the difference that "polish ones" call for ingredients used in "kiszony". The difference in taste is that polish one is much more spicy while kosher one is sweet.
After a quick google, it would seem that Polish pickles might/would contain more spices.
Due to their similar origin, Polish and kosher dill pickles resemble one another in preparation, making it difficult to distinguish between the two -- that is, until you taste them. While kosher dills are made with garlic, Polish dills are often made with more pickling spices, giving you a zesty, peppery pickle.
Polish dills contain more spices and garlic than either traditional dill pickles or kosher dill pickles. These pickles tend to be peppery and may be flavored with mustard seeds. Their flavor is similar to the kosher dill and they are served in the same way.