Fanon: Given his childish personality, even across decades, and Super Speed, it's common for fans to think that Herbie is a Cybertronian child that was lost on Earth.
Fanon Discontinuity: Fans go back and forth whether or not the 1997 film or Fully Loaded should be subject to this.
First Installment Wins: Though Rides Again was better received critically, the first film is by far the most beloved by the fanbase.
Old Shame: Fully Loaded might be this to Disney given that it was released right before Lindsay Lohan's rather public Creator Breakdown. Nonetheless, despite it not being heavily advertised, it was released on Disney+ whereas the 1997 film was not.
The 53 gum-ball on Herbie's door is absent in the original film's "balancing" scene. It was a conscious choice: the bottom of the door had to be cropped so the car could clear the ground to do the stunt, which including the number would have called attention to. An odd example in that it isn't conspicuous in the film itself (it's excusable for the time period and barely noticeable in the scene itself), but a still from the scene was heavily circulated promotion and merchandising of the film, even continuing to be used when the movie was released on video.
In Rides Again, the scene where Herbie drives up in the warehouse so he can trap the security officers among seized property features a blatant stop motion model.
The 1997 film contains quite a bit of Conspicuous CG, mostly involving Horace. It also shows up in some of Herbie's stunts (the lighting of those stunts even renders him as the wrong year of Beetle), and the reveal of Simon's factory.
It got better in Fully Loaded but some of Herbie's stunts are clearly CGI.
Values Dissonance: A lot of the humor involving non-Caucasian cultures from the first four films can be somewhat cringe inducing in the 21st century. Though in fairness, The Love Bug franchise never demonized any culture and most of its ethnic representation was actually quite Fair for Its Day.
Vindicated by History: The 1997 film was much better received by the larger fanbase after Fully Loaded.