Sayu as the lead? Surprising given that this is supposed to be Aichan's farewell single
Perhaps even more surprising - Sayu sounds good on this.
Not that I think it's that she's improved much vocally. More like they made a song that suits her vocals, much like how Shining Power seemed made to fit Yurina. Seriously, listen to CLAP! if you want to hear a song not suited for Yurina's voice.
Starts off with a nice, uplifting guitar riff. Then Sayu comes in with what I think is actually the chorus. It feels like a classic, fun idol song. I'm looking forward to hearing the whole song