While I admit Yurina can sound plain, I think her voice fits this song well, because her voice sounds soothing and it goes with the mood of the song. It also fits Yume de do up well, Anshinkan intro, etc. It's just the "pink upbeat songs" that I don't see her voice fitting, like Gag, because her voice isn't high and cute like Miya or Momoko's... But that's why she hasn't got many lines in Gag. So I think Tsunku also takes these things into consideration when sharing lines, and that's why Yurina has so many lines in this song.
Anyway, that was my opinion of Yurina's voice. But in general, I find it a joke to review Berryz voices seriously, because obviously none of them are really singers
Compare their singing to American Idol finalists and you should know what I mean with the difference.
Anyway, the perf was cute, but I'm not a big fan of the choreography. I somehow think that more could've been done with it. I've only watched it once, though.