I don't know about "best of the series", but it was very good, far better than its reputation! It's got a campy charm about it, and it features some of cinema's best-crafted child death scenes.

I think if Halloween III had been released as its own standalone film, instead of an entry into the Halloween series, it'd get a lot more respect from people. It might not be as famous as it is, since "Halloween" brand recognition is considerable, but shorn of the Myers connection, I could see Season of the Witch being a modest cult favorite.

I was joking, BUT this and the original are the only ones I really care about. So the honest statement would be "second best"