Okay. Sometimes,Riho can be good. But most times for me,her vocals....no. And it is usually just in performances,not audio. I understand that Riho basically has to focus on both vocals and dancing,so she might be a little tired.
Around 2012 time,I considered Riho because I felt that she was basically all the new girls had. Then Mizuki improved greatly and Sakura just HAD to walk in (XD). So I started doubting her alot.
In Help me!! performances,I felt like Riho was trying to overpower Sakura's vocals,which is something she shouldn't do because it hurts her rather than benefits her. And sometimes,I find Riho whining rather than singing (One Two Three).
Therefore,that is why I called her an intolerable singer. But guess what? It is my opinion. And nothing you guys can say can really change that fact.