I think the vocals sound a little too artificial for a lot of (Korean) fans (brutal honesty: they don't really sound like SNSD in this song) not really sure why they decided to release a Korean version of this song but I think the Japanese version will do well (which to be brutally honest is really their main focus and probably has been for a couple of years now).
I think releasing this kind of song in Korea could actually be detrimental to their popularity (in Korea), it's rare to hear this much vocal adjustment in a K-pop song and particularly for a group with such strong vocals to utilize it so much seems a bit odd (and slightingly off putting). I'm guessing this song will rarely (if ever) get a live performance (in Korea) and I'm guessing the title track for their Korean album will have more natural sounding vocals and be more to the tastes of K-pop fans.
Vocals adjustment aside I personally find both this song and dance performance to be top notch
Yoona Can Sing! Who Knew?