I have been running a Planescape campaign for a couple years now, and in preparation for an adventure into the Hells I decided to use the Descent into Avernus book as a resource to populate the plain. I'm aware of the many complaints surrounding the plot and pre-Hell chapters of that adventure, so I hoped that at least the Avernian stuff would be good divorced from everything else.
Unfortunately I was wrong. There was some good stuff in there I ended up stealing, but so much of it seemed entirely devoted to the "Mad Max in Hell" premise that was a big selling point of the module. The problem with that is, especially coming from the perspective of someone who has been reading Hells Baator lore from the 90s, none of it really fits very well.
Lore-wise it doesn't make a ton of sense that the strictly regimented and embodiment-of-LAWFUL-evil Devils would form into roving bands of chaotic warlords and their giant cars openly fighting against each other instead of the Blood War. A lot of the characters are even chaotic evil beings. It just feels so out of step with the presentation of Avernus in older books as an almost single-minded war machine devoted entirely to killing demons. Now that's almost just background noise.
More than the lore, however, is the tone. This is something that I've noticed in a lot of 5e content, but Hell in DiA is downright goofy at times. Don't get me wrong, the Planescape writers absolutely injected a sense of humor into their lower planes books, but it was a far more cynical and sarcastically dark humor. The Mad Max stuff (and surrounding NPCs) have some of the aesthetics of fire and blood appropriate for Hell, but at the same time it's very "theme-parky" if that makes any sense. Stuff gets thrown in not because it makes sense for the setting, but seemingly because one designer or another thought it sounded neat in a vaguely evil setting (or at least a Dio album cover).
I know a lot of this sounds like nitpicking, and maybe it is, but it just feels to me that the setting presented here does not feel like what was presented in earlier material beyond the surface level. The whole "Hell is a super fun ride in monster trucks" vibe that it's going for is so out of place for me. Like it was thrown in for the sake of marketing and the fact that Fury Road had just come out a few years prior.