I'm not going to bother comparing the two, it is a pointless exercise to be perfectly honest. These days we have to worry about Muslims far more than Nazis though.
My concern is a comparison between the differnt ways the two are treated by the Left. Their response to the Nazis is hysterical and self-serving, using peope's justified outrage at Nazism to attack even moderate, centre-right ideas by casting aspertions. Their rather different response to Islam is quite revealing.
Of course this is not meant to accuse everyone on the Left of rank hypocrisy, there are a few people firmly of the Left who recognise the danger that Muslims pose to Western, liberal principles (free speech, rule of law, individual rights, women's rights, democracy) and are capable of attacking Islam with the contempt it deserves.