As with most Seinfeld, the plot ideas for this episode are very original, but as with most of Series 8 stretches its observations on every day life beyond the point of seeming realistic or funny.
Elaine has the titular and best plotline in The Muffin Tops. She ends up in a confrontation with an old colleague after he steals her idea to open a store that sells only the top half of muffins. While not very realistic, it is amusing to see how Elaine's disdain for the bottom half of muffins escalate into the opening of a top-only store.
Kramer's storyline, an ironic reference to the exploits of the real life Kramer, fails to gain comedy momentum beyond recognizing where this joke came from. Jerry's story has its amusing moments but lacks the originality or wit of previous episodes. George's exploits in this episode, like Elaine's, succeeds in being amusing, thanks mainly to the inclusion of the always funny Larry David-voiced Steinbrenner, but isn't recognizable as something that could happen in real life.
Below average, even by the poor standard of series eight.