I'd say about 70-80% of the story lines were good to excellent, and even the mediocre or few bad episodes were carried by the strength of the charming lead actors. William Katt played a high school teacher named Ralph Hinkley who was given red power suit by peaceful aliens only to be teamed up with a neurotic FBI agent named Bill Maxwell played by Robert Culp. Connie Sellecca offered the human touch as Ralph's girlfriend Pam Davidson. Katt's character lost the instruction book to the power suit in the pilot episode, leading to a very original and hilarious version of the ever familiar superhero story. But right from the start this series was plagued with problems such as a silly lawsuit from DC comics, who asserted that Stephen J. Cannell stole their Superman character. Cannell won the landmark case, but many potential merchandising companies were scared off by DC and Warner Bros. studios who still held a grudge against GAH. Then mere weeks into the show's 1981 debut, President Ronald Reagan was shot by a would be killer named John Hinckley...it just so happened that the main character's name on GAH was Ralph Hinkley. The ABC network even went so far as to dub over "Hinkley" with "Hanley" in a couple of early episodes. Speaking of ABC, they were probably Cannell/GAH's worst enemies. The network gave the show late starts in all 3 seasons, while other shows began their season rightfully in September, GAH would be forced to debut as late as October or November. ABC also consistently pre-empted GAH with other events (like major league baseball) during the 2nd season.
ABC then put GAH in a hole that could never be dug out of, the network drilled into the publics mind that GAH was nothing but a campy children's series that wasn't worth bothering with. The network nearly always promoted the series with shots of series star William Katt being silly and crashing into walls. GAH did have moments of camp and silliness, but it was written on an adult level and played straight so it was by no means an Adam West type camp series. There was more to this series then Ralph simply being an inept Superman. Sometimes ABC wasn't even close in it's promo ads to the plot of an episode, billing it all as Saturday morning kiddie fare. The series never recovered from this type of grossly unfair advertisement. It seemed like a lot of people just never understood the concept behind GAH, and no matter how many times you valiantly explained the premise of this show to people, it simply didn't matter. The damage was done. This was seen as simply an idiot children's series by way too many folks out there. Unfortunately that was the nail in the coffin. No TV show was going to survive being up against such odds. After 3 very short seasons and 44 episodes, The Greatest American Hero was cancelled by ABC in the spring of 1983...only to be replaced with two flimsy sitcoms that received even lower ratings and ultimately bombed. GAH has earned a "cult classic TV" status over the years, which is quite an accomplishment for a show that has barely been rerun in the continental United States since the 80s. Yet GAH could have been even more then that had the playing field been not so ridiculously lopsided against the show. There's a much anticipated DVD release coming around the corner, hopefully it will finally give this series justice and the fair handshake it never got.