I agree with this. The Fantastic Four have the best rogues in the Marvel Universe. And definitely better than Spider-Man's.
As a rule, DC has better villains than Marvel does. Like consider Vandal Savage, Dr. Destiny, AMAZO, Starro, Chronos the Time-Thief, Grodd, Deathstroke, Sinestro, Darkseid. But Fantastic Four alone allow Marvel to catch up.
Superman historically has always bad a weak rogues gallery. Originally Siegel and Shuster since they more or less were inventing the superhero genre had Superman (not yet capable of flight) fight ordinary bad guys, and so on. Lex Luthor was just some red-headed thug, and then he got accidentally bald in a printing error and the version of Lex you have now was created later and modeled on Dr. Sivana over at Fawcett's Captain Marvel (now Shazam). As Neil Gaiman said:
"Compared to most A-list comic characters, he has almost no memorable villains. Think of Batman, locked in eternal combat with nocturnal freaks like the Joker – or Spider-Man, battling megalomaniacal weirdos like Dr. Octopus. For Superman, there’s pretty much only bitter, bald Lex Luthor, forever being reinvented by writers and artists in an effort to make him a worthy foe. Superman’s true enemies are disasters like earthquakes and hurricanes, jet planes tumbling from the sky, enormous meteors that would crush cities. Superman stands between humanity and a capricious universe." (
https://www.wired.com/2006/06/myth/)
My favorite Superman bad guys are Brainiac and Mr. Mxyzsptlk. The latter especially is a really unique kind of villain. To me those two are his greatest villains but they also take Superman to a higher dimension and plain and away from the Clark Kent side of things. So while they are better than Luthor, you get to see Superman/Clark Kent more in action when he's dealing with Lex than with them. And Superman simply doesn't work without Clark Kent. The X-Men have interesting villains: Magneto, Apocalypse, Juggernaut, the Hellfire Club, Mr. Sinister (Jackal isn't fit to shine his shoes), the Sentinels, William Stryker, Phoenix, Mystique, Sabertooth among others. Although a movie like LOGAN works without any real special villains. And the mutant/discrimination theme works without there really needing a bad guy. So there you have a case where you have great villains and the issues on how they fit in the fabric of the general story and concept of the heroes.
In general, I think the two greatest villains in comics are The Joker and Dr. Doom. Dr. Strange also has quite an underrated bunch of villains: Dormammu, Nightmare, Shuma-Gorath. Nightmare tussled with Ultimate Spider-Man and that was great. Iron Man has maybe the worst rogues for any major superhero.
Spider-Man's rogues is better than average. But they aren't as good as it should be or could be, and there's still some issues with how they cohere.