It's heavily focused on comedy, we'll see characters from 4 different worlds interact with each other, and it works, many dialogues and situations are funny, I think that konosuba is the closest one in terms of atmosphere, and the tone is similar, it's the same type of comedy.
Now, most of the jokes are what we could call "private jokes", meaning that you won't be able to understand some dialogues if you haven't seen the shows. I mean, you can understand many of them simply with the context given in Isekai Quartet, you can deduce some meanings, but I think Isekai Quartet is way more enjoyable if you've seen at least 2 or 3 of the isekais. ( I'd say that Youjo Senki is the "least" required to enjoy Isekai Quartet because this one has fewer "main characters" than the other 3. )
I think that the concept of gathering 4 isekais in one anime is pretty cool and fits the genre, it's especially funny to see the new friendships between from characters that are alike ( aswell as the unexepected ones ) but I can understand people who are disappointed by this choice to make this story a comedy one with chibi visuals. I truly believe that this angle worked out well in the end, but if you take a step back, Isekai Quartet might be lacking ambition. The scenario is almost non existant, and well, I guess that it could have been possible to think of a more complex, exciting story to link those 4 worlds together.
All in all, i if you enjoyed at least 2 of the 4 isekais that are in this anime, I can't think of a reason that would prevent you from liking Isekai Quartet aswell. This show is all about fanservice, meaning that you'll see more content that involves characters you love, it's easy to watch and the opening and ending of both season are all good songs, what else could you ask for ?
( I give one more point to the season 2 because I think that the interactions & dialogues work even better than in S1 )
