Well, as a fan of Chihaya-furu, they just have to start with THAT poem. I say props to them, as it certainly caught my attention.
That said, I liked the older brother story more. Hiroko was so adorable as a true Yamato Nadeshiko. Thing is, I think I'm too heavily influenced by NTR that when older brother said to welcome his younger brother, I can't get NTR out of my head considering younger brother is a playboy.
Regardless, I think I'm hooked now. I know that the stories are only loosely based on the actual history of the poems, but hey, if it's interesting, might as well know some backstory and familiarize myself a bit more with the poems of karuta (Chihayafuru 2nd season is coming soon after all)