For me, attraction is always a whole package. I tend to become attracted to someone after spending a bit of time with them, not on first sight. So I can't say with any certainty how much scent plays a role in that, but I'm sure it does.
I will say, though, that strong cologne will turn me right off. I used to get really bad headaches from just about any fragrance. It's gotten better, fortunately, where now it just hurts my nose, except Axe. I can't be in the same room as someone who reeks of that crap. So if someone is otherwise perfect, if they smell like they fell into a vat of perfume, it's not going anywhere.
That being said, my husband was willing to be trained to stop bathing in cologne. That was when it still gave me headaches. We met at the end of the day, after it had worn off. The next morning, he put it on. I sent him outside, informing him that it gives me headaches. This repeated daily until he caved and stopped wearing it. He still forgets sometimes, but my sensitivity has decreased. It's not so bad with the higher quality stuff, but cheap cologne is way out.