I didn't rush till first semester sophomore year, and I lived in a very Greek-heavy dorm, so after seeing my floormates rush & pledge for 2 semesters I was pretty savvy about what I wanted.
As far as national standing though, I had ZERO idea and I would wager most of the campus was the same way (again, this was pre-internet). The first we had an inkling of things like that was that the card store in town had pin pillows for some groups and not for others - they only had for "New York sororities" whatever the heck that meant.
I think it was kinda like my mom saying Seventeen magazine was more New York than Teen, but I digress...