People who know that name will already have a very firmly held opinion of the man and nothing anyone says or that he does is going to change it.
It's really up to you to decide.
Here Michael Sladek makes an attempt to get past the hyperbole, most of it created by Kostabi himself, and to show us the "real" Mark Kostabi while at the same time trying to extract from Kostabi some sort of explanation of, not just who he is, but what he is. This is no easy task as Kostabi is, quite clearly, unsure of the answer to either question.
Mark Kostabi was a big noise in the art world during the 1980's. His paintings sold for a LOT of money, he was mixing with Warhol and Basquiat, he was the enfant terrible of the art world and he loved being so. This was the man who urged people to take the "L" out of play and the "R" out of free. He was rude, obnoxious and opinionated. He wanted to make money and he didn't make any secret of that fact. Most controversially he created "Kostabi World", his version of Warhols factory, where he employed young artists to both produce his work and also to come up with the ideas...he had removed the artist from the art.
The film itself is as engaging and entertaining as its subject. He is utterly contradictory and so we hear talking heads from various luminaries and friends that paint an utterly contradictory picture of Kostabi. Some hail him as a genius and a warm, loving individual while others decry him as a charlatan and the cruelest of men. While you may not enjoy his work (or even believe it is "his" work) there isn't any doubt that Kostabi is an engaging screen presence and a proper character in a world where fame normally attaches itself to only the most anodyne of people (please stand up Leona Lewis et al). Simply or being who he is he deserves all of his success.