*Spoiler*
I will be honest, I've never liked Snape. Never.
There was always a part of me that knew he may have been working for the good side all along, but still I don't think that meant he was a good person.
I thought he was malicious up until the day he died.
However, he is very much the anti-hero.
Without him, Voldemort may never have been destroyed.
He played an instrumental part in that, but he never did it for Harry, Dumbledore, or anyone else, but Lily.
JK Rowling actually said in an interview once that if Snape had not been so obsessed with the dark side, Lily probably would have fallen in love with him and married him. Snape set his own course. He can't blame that on anyone else, but himself. But throughout the whole series, he constantly blamed it on James and then punished James' son for it.