Brown used to publish on their Admission Facts page a breakdown of admission rate by standardized test scores. Dartmouth and a few other schools including Princeton used to publish similar data.
The old pages seem to have vanished from the internet, and the colleges no longer publicly divulge that sort of data.
An old thread on CC referring to the data is here http://talk.collegeconfidential.com/parents-forum/1690095-college-admission-facts-opinions-and-myths-p1.html
References to the data in the thread suggest that the closer you get to a perfect score, the higher your odds of admission, even compared to scores otherwise considered excellent.
My personal feeling is that - all other things being equal - the odds of admissions at most highly selective schools is better with a > 75th percentile score as compared to a < 75th percentile score.
Current Brown 75th percentile score is a 1550.