Early Simpsons is Season 1 - 8 which almost everyone thinks is good except for people who think Season 1 is too wonky (the wonkiness comes from some Season 1 episodes more resembling longer Tracey Ullman shorts than actual Simpsons episodes) or purists who think Season 8 was when the Simpsons started to run out of ideas. Seasons 9 - 12 was when Mike Scully is showrunner, and it's a contentious 4 seasons. Most Simpsons fans would say that the decline in quality was underway by the time Scully was showrunner. The argument is mostly when. Did the decline began in the second half of Season 8, did it happen in Season 9 with that infamous episode with Skinner, did it happen at the end of Season 10, did it happen in Season 13 when Al Jean took over showrunning duties, and so on? Everyone has their own hot take.

I'm a traditionalist. The Tracey Ullman shorts are awesome although mostly interesting as a historical curiosity if you're not a Simpsons fan, Season 1 - 8 are the good seasons, the Scully years are hit and miss, with more hits in Season 9 - 10 and more misses in Season 11 - 12, and Al Jean taking over showrunning duties is when the Simpsons became what many people term Zombie Simpsons. The movie is whatevs and while many Simpsons Youtubers swear by the newer seasons not sucking as hard, especially since Al Jean is no longer a full-time showrunner, I can't find myself caring after all these decades. Plus, it's very painful hearing Marge's VA these days.