I must admit to having some reservations about this film, I expected a surplus of toilet humour, cheap gags, and poor slapstick - but I was pleasantly surprised! Okay, maybe some of the jokes were tacky, but once you're into the film you don't notice!
This film shows a group of heros, that have powers, but unlike the X-men where you see the group save the day, here you see the group bum around HQ, get up in the morning, go out to a bar - just mundane stuff. It's a great film concept, and it's pulled off really well.
The low budget may put some people off, but I think it only adds to the film's feel and character. The Specials barely have a budget for a TV, and having elaborate sets and costumes would have just clashed with that concept. For example, the scene where Weevil visits the crusaders in a huge, ornately decorated office is an excellent contrast to the rest of the sets.
I would recommend this film to everyone, if you've seen Mystery Men, but didn't like it, don't let that put you off - The Specials is very different (the characters actually have decent powers).
Finally, if you can, get the DVD with the commentary - it's the only commentary I've actually listened to the only way through, it's hilarious!