I saw this movie in its initial release, in a movie theater, back when I was around 13 years old. I haven't seen it since, and I doubt that it has stood the test of time, so this is just an explanation of why the film existed in the first place, and the context in which it must be understood to make any sense at all.
The movie was essentially a fan film, in the same way that the string of forgettable Elvis movies were fan films. It was a piece of fluff designed solely to appeal to fans at the time of the pop band Herman's Hermits (or more specifically, it's lead singer, Peter Noone). Long before music videos began on MTV, these kind of films were essentially just that - a chance for young moviegoers to see a popular band perform their hits on screen.
You have to remember that this was not the 1960s that most people tend to think of when they think of the '60s. This was not 1968 or 1969. This was 1966, two years before the assassinations of Robert Kennedy and Martin Luther King. America was still a relatively innocent place, and there was still room for lightweight pop-rock with catchy melodies. And Herman's Hermits filled that demand with some very catchy and memorable tunes from the period, as part of the overall British Invasion. If you're looking for hard rock or social commentary, look elsewhere. This was, at best, pop-rock - some would say bubblegum; it probably appealed mostly to younger teens, and girls who (like the one I went with) thought "Herman" (and his British accent) were cute. But the band definitely succeeded on the radio. The band sold over 60 million records, with at least 10 hit singles, ranging from "I'm into Something Good" and "Mrs. Brown, You've Got a Lovely Daughter" to "There's a Kind of Hush" and "I'm Henry VIII, I Am".
The point of all this is that, going in, no one really expected it to be a good movie - the silly plot was beside the point. The young teen audience who bought tickets did so simply to hear the music, to see the band, and feel "a part of the scene" at the time. I don't remember much about the movie, other than that it was more or less exactly what I had expected, a harmless piece of Hollywood fluff that showcased a current band that I liked at the time. I doubt that it can be understood or enjoyed outside of that simple context.
So basically, your reaction to this movie is likely to depend upon your reaction to Peter Noone and Herman's Hermits. As I said at the start, it was a fan movie. If you were a fan of the group, you'll probably enjoy it, despite its obvious shortcomings. If you didn't like the band, you won't like the movie. And if you never heard of Herman's Hermits, then you'd probably be better off skipping the film, and just listening to their Greatest Hits collection.
