First off, let me say that I have a clear bias here as I am a current third year at Columbia. That being said, I would warn strongly against using the USNews ratings to decide which medical school you want to spend the next four years of your life at. While "Student Selectivity" is important as a general idea, there is more to being a good student and a decent person and especially a colleague than an MCAT score, a GPA, and an acceptance percentage (the components of that selectivity score FYI).
While it is true that Penn was the first medical school in the colonies, Columbia, founded in 1767 was the first medical school in the colonies to award the degree of MD. ( <a href="http://cpmcnet.columbia.edu/dept/ps/descrip.html" target="_blank">Columbia History Info</a> )
As far as reputation and academics I would honestly say that you are splitting hairs to say that one of these schools is clearly better than the other, furthermore, because they both have distinct curriculums and vastly different ideas about the fundamentals of medical education, the two systems can hardly be compared to each other. Think about your style of learning and what you prefer, however, keep in mind that you have no idea what will work best for you in medical school, this is learning on a scale that you have not seen as a college student and will never see again, no matter where you went to college or what your degree is in. This is learning that ends up with you making life and death decisions up close and personal. The liklihood is that you are good students, and will make whichever system you end up with work for you and not vice versa.
Also, you should think about Philly vs. NYC personally, I hate philadelphia and would have been bored out of my mind there, no offense intended, I have spent a good deal of time there and really felt that the city could not hold a candle to NYC on any scale with which one chooses to measure the two.
I would encourage you to return to both schools for "revisit" and meet as many current students and possible future classmates as possible. As others have said, if you have gotten into both of these schools, you will likely do very well for yourself anywhere.
As far as the match etc., I can only speak for Columbia in this regard. I can tell you that we were recently told that our class (the class of '03) had a USMLE step 1 average of 231. To put this in the proper context, passing=180, national average=215, Standard dev=15-19. What this means is that, on average, Columbia students scored nearly one standard deviation above the national mean. In addition, this class only had about two weeks to study for the boards due to a scheduling error that will never be repeated and we still managed to get the highest average score that Columbia has ever seen.
In terms of the National Match, this years fourth year class at Columbia had an excellent match with 7 people matching in neurosurgery, 7 people (actually low for us, likely to be about 20 or so next year b/c ppl taking years off for research) matching in orthopedic surgery, about 3 or 4 who matched in combined plastics programs for which there are about 90 spots nation wide, and a number of people matching in other categories at number one residencies i.e. Brigham/Womens, Mass General, CHOP, CH of Boston, etc...
Anyway, hope this helps, if you have any questions, let me know.
JB