Her pronunciation is easier to hear , You can hear it in their commentary on All MV video collection 2 wherein Sakura ask Rei to comment in English on Ano Kyoushitsu MV.
Yuri's pronunciation is native level though. She sounds like an American. You can hear it on Nogi Eigo when she speaks with her normal American accent but then switches to a Japanese style accent so the other members can understand her.
I want to hear Rei sing this part while blindfolded. I can't wait'til tonight, baby let's go You know what I want, gotta give me some more Need you right now and I won't let you go, go, go I can't wait'til tonight, baby let's go, go, go Open the door, now we're ready to go, go, go Boy I need your love, gotta give me some more --- Reiland is so hot that even make this guy's waki, sweating~
yeah yuri's english is definitely better. As for clarity, I think it's mostly because Yuri's voice is super soft