People tend to view the series solely in terms of the Alan Moore run, which may be because the rest of it has either never been collected in trade form or is otherwise notoriously difficult to find. It's generally accepted that the Wrightson-Wein run is pretty good, the Brian K. Vaughan run... isn't, and that the tail end of the Plasko run is required reading to fully get the Alan Moore run.
Doug Wheeler's run often falls into this almost by accident, since it was the only run to be totally and utterly forgettable. Even with the benefit of hindsight it doesn't really have any fans.
Nancy A. Collins' run has its share of (mild) detractors; she basically reset the series to the end of Alan Moore's run with a Swamp Thing that was (relatively) mainstream-friendly and akin to the Wrightson/Wein and Plasko runs, as she concentrated more on Character Development, exploration of Cajun culture and an expanded supporting cast than horror (though it's worth noting Alan Moore was a fan of her work on the character).
Mark Millar's run too falls into this line as well, given the fact that it later came out that much of it was plotted (uncredited) by Grant Morrison to give the inexperienced Millar a leg up in the industry.
Brightest Day and The Search For Swamp Thing were declared non-canon by Swamp Thing fans for the way they scorched-earth every Swamp Thing story written (as well as "The Anatomy Lesson") in favor of Geoff Johns going all "Captain Yesterday" and basically resurrecting Alec Holland simply so he could die again and become Swamp Thing for real and kill the Alan Moore version, who was described as being a corrupt parody of Swamp Thing (granted, because Swamp Thing had been possessed by a Black Lantern Ring). Thankfully, the New 52 flat out erased this from canon.
Genius Bonus: During the Rick Veitch run one of the candidates Constantine picks to embody The Sprout is Solomon Grundy. When Swamp Thing first encounters him, he doesn't recognize him at first, but then suddenly realizes that he knows him. This is a sly reference to the fact that Swamp Thing had met Solomon Grundy before, but it happened in a story that Len Wein had declared was non-canonical when he took over as editor of the rebooted comic in the 1980s. (Swamp Thing and Constantine actually survived Crisis on Infinite Earths and retained memories of the way the world(s) used to be.)
Growing the Beard: The character is generally considered to have changed hugely for the better when Alan Moore did away with "Alec Holland" trying to become human again, recast Swampie as the anthropomorphic personification of all plantlife and began exploring nature mysticism. Most writers afterwards have followed this angle.
Moral Event Horizon: Swamp Thing's daughter Tefé burns through all audience sympathy when she enforces a Sadistic Choice on a man who started a forest fire, forcing him to choose between the life of his daughter and his wife. She doesn't kill anyone, but his family get to see him choose.
My Real Daddy: Len Wein helped create Swamp Thing (and more), but Alan Moore's complete rewrite of the character is the one that lasted.
One True Pairing: Alec/Abby has become such an iconic couple since the '80s that it's easy to forget that in the original Len Wein run, while he does rescue her a couple times, they had no romantic tension at all; Abby was firmly with Matt Cable, and Alec remained devoted to his murdered wife Linda. Then Alan Moore used the pairing for his fascinating examinations of nonhuman personhood and offbeat family structures, and the rest was history.
Production-Related Period Piece: Early reprints of Alan Moore's run began with "The Anatomy Lesson", the second story Moore scripted for the title, which begins with Swamp Thing already captured by the Sunderland Corporation. Beginning in 2009, Moore's first issue was included in reprints as well; however, even though that story details Swamp Thing's capture, it also continued the preceding storyline by Martin Pasko, which would not be reprinted until 2017.
Shallow Parody: Volume 2, Issue 3 features a children's television show host who espouses a series of questionable lessons on how strangers are just friends you haven't met yet...all in the service of a child-eating demon he sold his soul to. Of special note is how he likes to use the term neighbor. Said issue then features one of the characters talking about how dangerous, cruel and hostile the world is and that kids should be taught to avoid strangers. Salient points, but Fred Rogers never taught children to interact with strangers outside of their parents' supervision, at all. To add to the shallow-ness, the evil kids show host, before making the demonic pact, was a spineless schlub who let his bosses push him around and was often accosted by them for showing violent cartoons; whereas Fred Rogers, while not perfect, made several principled stands in his life, and had a generally negative view of cartoons that he saw as "mindless violence", even including G-rated slapstick.
Squick: Most things about Anton Arcane, especially his incestuous designs on Abby after he possesses Matt Cable's body.
Complete Monster: Dr. Anton Arcane, from this film and its sequel, is a wicked Mad Scientist with dreams of immortality and power over the world. In the first movie, Arcane seeks to exploit the invention of the noble scientist Dr. Alec Holland, a solution capable of solving world hunger, having the staff of Holland's facility massacred by his mercenary entourage while personally murdering Holland's sister. Arcane later takes the formula for himself while testing it on one of his own men as gratitude for procuring it for him, mutating him into a freakish pig-man. In the second movie, Arcane facilitates the experimentation on countless dozens of innocent people, resulting in most of them killed in the process and those who survived afflicted with horrific, mutative growths, while throwing away the lives of his own subordinates to use their DNA to extend his own life and eventually killing his own daughter to reverse the degeneration of his body. The epitome of selfishness and dark ambition, Arcane's ultimate wish is to force the world to bow to him or starve, concerned only with his power and legacy above even the lives of his closest friends and family.
What Do You Mean, It's Not for Kids?: An accidental case: the original region-1 DVD release of the first film packaged the unrated cut (with significantly more nudity than the theatrical cut) in a case which still bore the PG rating of the theatrical cut. The "unrated" cut was created for European release in an effort to make it Hotter and Sexier. This version was never meant to be seen in America due to a contractual clause by Adrienne Barbeau, whose nudity was shown in a bathing scene in the river. Because of this, all American video releases since said DVD are the PG-rated version until the Ultra HD Blu-ray release.
). The name of the demon's TV persona? Uncle Barney.