No, it's not "The Pirates of Penzance." Yes, it's campy and often cheesy.
However, I've always found this film to be delightfully charming in its own way. Following the storyline of "The Pirates of Penzance" yet not afraid to veer off in its own wild and eccentric direction, this one's an unexpected charmer. It showcases a lot of the songs from the original operetta, done with true panache. Altogether, I find it much more entertaining than the work it's based on (in particular Kevin Kline's bland rendition thereof).
The Pirate Movie is very much an early '80's film that comes accross as dated, and yes, some of the original songs in it are wretchedly silly. But it has a few really neat original numbers in it as well, in particular the closing song.
For swashbuckling, derring do, witty repartee and piratical naughtiness this one can't be beat. It's hilarious most of the time, though it did illicit quite a few groans from my friends and I.