Personal opinion: I think the acid test of a manga is how well is holds up on re-reading. Two of my favorites by that standard are Flying Witch,YKK, and this one. Last week, having nothing in particular to read, I restarted Sono Bisque Doll from the beginning and found myself, from the first chapter, with a silly and happy grin on my face.
I could list all the things that make this a great manga, but you already know them. A new chapter always means a wonderful day.