It just struck me recently and I'm sharing.
As a millennial who enjoyed these shows as a young(er) adult ... I cherished them both, and at the time probably like 30 Rock more, and probably would have said that it's "the better comedy".
Over time though I've noticed I basically don't really think about 30 Rock ... frankly I almost certainly think about Seinfeld more ... but Community has "seeped in" to my TV subconscious fabric.
If I were to re-watch either right now, it'd be Community hands down. It'd be heart warming and comfortable and, I suspect, more relevant or still meaningful. By comparison, I wouldn't be surprised if 30 Rock would feel more dated, "noisy", and kinda culturally narrow and specific in a not-coincidentally SNL-like way.
30 Rock may still be "the better" TV Comedy (whatever that means). But it was written by a TV writer about making TV in New York, while Community was written about TV and its fans, IE "us", living in any random city.
Yeah 30 Rock is rapid fire, like The Simpsons or Airplane! It's so dense with jokes and they are of a very high quality that sometimes you'll be laughing so hard you miss the next one. Community is more about needling at tropes and formulas and really just deconstructing what a TV show even is or can be. It's a different beast entirely, and I love it too (except for the gas leak of course)
It's funny with the gas leak ... I remember not really minding it at the time ... but I'm not sure I can remember any of it!