I like the American version... it looks like a Buick, and I don't think Buicks look that bad. If I was in the market for a car now, I'd consider a Lacrosse... seems like a pretty good value for the price.
I don't like the Asian one, looks like it's trying to imitate a Hyundai/Kia which is trying to imitate a real luxury car... two degrees of imitation.
I DEFINITELY don't think the Asian tail lights fit with Buick's American demographics. I know they'd like to have younger customers, but young as in 30s, not teens.