Sixten agitates for Azumanga with an essay. It's good effort, although I see that nailing the secret is hard. He comes very close with the "transition between funny and heartful".

Little Snow Fairy Sugar and Mahoraba – Heartful Days are the only two J.C.Staff series I consider superior to Azumanga.

IMHO, Mahoraba is nice, I even have note collection for it, but it's no Azumanga. It is overlong for its story and is full of filler, it has many more animation defects, characterization of Kozue's alts is uneven (Saki is a person, Chiyuri is a caricature), Shiratori takes a very long time -- over 8 episodes -- to start doing his job, and the big story is not properly resolved despite the length. In short, it's not made to the Azumanga's standard of quality, not even close.

On top of uninspired execution, where Azumanga blazed new trail and became a yardstick for innumerous wannabees, Mahoraba was formulaic. Its only claim to fame is the unusual composition of the harem.

Certainly, Mahoraba did an exempliary job in making brain damage look cute, without the intensity the ef brought into the discourse. It's relaxing to watch, especially if you know that it has a good end (my R index for Mahoraba is 4.5). And the comedy is at the level of Azumanga. But it's not enough to enter the pantheon, as far as I am concerned.