I was actually really disappointed when I listened to the Korean version. First of all, I was just confused as to why Jessi's intro (as well as that bridge to the last chorus) reminded me so much of the, uh, chorus(?) of SHINee's Lucifer (I don't know, I don't really know things about boys). My favourite part of the Korean was actually the weird rap break near the end, because it was the most exciting part of the song. There just isn't enough distinction between the chorus and the verses.
The English version, however! My reaction was pretty instantaneous. This was definitely meant to be in English, despite what I thought with the teasers. It flows better and just seems to be more suited to the English lyrics. Definitely feeling the Teddy Riley influence

Not going to promote in the US, huh Zoo? Well, I guess I'll still be wondering how it would do over there then.
On a final note, Yuri at 4:32-:34
EDIT: Oh yeah, forgot to mention - they should've made the two MVs completely different, in my opinion. I know it's SME, so they wouldn't, but they should have.