The fundamental difference in most programming languages is that unless the unexpected happens a for loop will always repeat n times or until a break statement, (which may be conditional), is met then finish with a while loop it may repeat 0 times, 1, more or even forever, depending on a given condition which must be true at the start of each loop for it to execute and always false on exiting the loop, (for completeness a do ... while loop, (or repeat until), for languages that have it, always executes at least once and does not guarantee the condition on the first execution).
It is worth noting that in Python a for or while statement can have break, continue and else statements where:
break - terminates the loopcontinue - moves on to the next time around the loop without executing following code this time aroundelse - is executed if the loop completed without any break statements being executed.N.B. In the now unsupported Python 2 range produced a list of integers but you could use xrange to use an iterator. In Python 3 range returns an iterator.
So the answer to your question is 'it all depends on what you are trying to do'!