From the album video, a ranking of J=J in the category of "head acting/emoting"
1) Sayuki - She is really natural, I could watch aUsually lo shot of her for the entire song without it being awkward
2) Yuka - Almost as good as Sayuki, but not quite as natural feeling
3) Tomoko - Half the time she looks good, the other half is just awkward looking.
4) Karin - Her patented smile-stare has ended up looking both awkward and creepy looking in this clothes-less, close up type shot. Usually she's a bit more natural than this, so maybe she wasn't into the idea.
5) Akari - Had no idea what she was doing and where she should be looking, the poor dear. This just wasn't her shoot.
Can't help but compare them though since that's all the video is