Dear lord, Yui surprised me. Radio Happy was as fun as expected, but I wasn't expecting her interview to be like a crossover of Miria and Shiki. She didn't strike me as the childish yet mischievous type.
Kyoko's song doesn't really stick out from the other happy-lovey-cooking songs (i.e. Apple Pie Princess), but damn, is she adorable when flustered. Yuka too, to a lesser extent.
Haven't gotten around to listening to the other two yet, not that I particularly care for Yumi.
As for 346Pro Idol Selection vol. 5, Kirari no Uta was definitely the highlight, but Miku doing a jazzy version of Anya's You're Stars Shine on Me was also great. I didn't care for Rika's singing or Riina's original song though, so Twilight Sky gets another skip for me.