@ricck1 - There is no doubt that Yale is a fantastic school for someone who is looking for a strong premed program, but international rankings directly contradict your statement that " Yale is generally regarded better in the sciences and premed, particularly biology". In fact, it’s the opposite.
http://grad-schools.usnews.rankingsandreviews.com/best-graduate-schools/top-science-schools/biological-sciences-rankings
http://www.topuniversities.com/university-rankings/university-subject-rankings/2013/biological-sciences#sorting=rank+region=+country=+faculty=+stars=false+search=
http://www.timeshighereducation.co.uk/world-university-rankings/2014-15/subject-ranking/subject/life-sciences
http://www.shanghairanking.com/FieldLIFE2014.html
http://www.timeshighereducation.co.uk/world-university-rankings/2014-15/subject-ranking/subject/physical-sciences
http://www.shanghairanking.com/FieldSCI2014.html
http://www.topuniversities.com/university-rankings/university-subject-rankings/2014/physics#sorting=rank+region=+country=+faculty=+stars=false+search=
http://www.topuniversities.com/university-rankings/university-subject-rankings/2014/chemistry#sorting=rank+region=+country=+faculty=+stars=false+search=
It’s really a moot point for most undergraduates - both schools have excellent programs, and students who are lucky enough to have a choice between the two should be looking at more than just rankings.