The rating (7+ at the time of writing) on IMDB might lead you to expect an undiscovered classic. In fact, it is a modest low-budget effort which has stood the test of time pretty well.
The film concentrates on the more mundane aspects of the rock and roll lifestyle: the rehearsals, the on-stage jealousy, the back-stage bickering, having to deal with "the men in suits" who want to package the band like a packet of fish fingers. We also see lots of "it's grim oop north" staples, such as terraced houses, pigeon lofts, dirty canals and a steel foundry. Given the budget, this was a wiser move than attempting to capture Slade in all their foot-stomping grandeur at the height of their fame.
From a technical viewpoint, the sound is a bit iffy and the lighting in many scenes seems designed to conceal rather than illuminate. Tom Conti sleepwalks through his first big-screen role, but then his character (high powered marketing executive with no interest in pop music) is fairly one dimensional, anyway. Johnnie Shannon, however, as the low-life agent who dumps the band and then tries to get his hooks back into them when they make it big, is excellent as the thug with a friendly face.
Surprisingly, the members of Slade make a decent fist of the acting, and the soundtrack contain two bona fide classics among the more bog-standard 12-bar fare. Don Powell has a couple of decent slapstick moments, Noddy and Jim have some good confrontation chemistry going, and Dave Hill plays an annoying buck-toothed twot with a stupid haircut ...
Though it is probably no better than a decent episode of "Aud Wiedersehen, Pet", its saving graces are its gritty authenticity and the songs. I particularly enjoyed the machine gun assault on the pirate radio station in the Thames Estuary (Radio City) - it impressed my kids no end when I told them this actually happened in real life and it was later confirmed by Noddy Holder in the "extra features" interview.