I recall this film being big in the early 1970s. It was George Lucas's first hit, and while a severe comedown from THX 1138, it was not quite as mindnumbing as the Star Wars films.
Some good performances in a frothy, light film, it did not make one hate Lucas, but it was not as dark nor 'realistic' as, say, The Lords Of Flatbush, which came out a year later. That film starred Henry Winkler in a proto-Fonzie role, while his future Happy Days co-star, Ron Howard, starred in this film. Lords was also a better film than AG, if for no other reason than its low budget feel made it seem more realistic. Also, its thugs acted the way one stereotypically thought of gang kids from the 1950s.
Here's the trailer for AG:
