I’m looking at both these schools and am still trying to decide which I should apply ED to. I’m interested in engineering (possible cs or biomedical) and possibly taking some business courses.
Both are obviously fantastic and you will get a top notch education at either.
Penn’s engineering school is extremely strong independently and made even stronger by its integration with the rest of the university. Here are the results of the post-graduate plans survey for the Engineering class of 2014 (http://www.vpul.upenn.edu/careerservices/files/SEAS_CPSurvey_2014.pdf). With high starting salaries and great career placement across a number of different fields, Penn SEAS is a great choice for anyone considering a career in engineering.
Since you are interested in taking some business courses I would say that Penn is a really outstanding option for you since it has the strongest undergraduate business program in the world right on campus. Penn’s one university policy allows students to take classes and do research across Penn’s other undergraduate, graduate and professional schools as well as in its research institutes. That means you have a lot of options in tailoring your education to your interests and needs including adding a dual degree from another of Penn’s undergrad schools, adding a University Minor which combines the departments of two schools to create one, cohesive program of study, and simply taking classes in those schools as well.
If you are interested in biomedical engineering research, Penn is also an outstanding place to be since Penn Med, the Hospital of the University of Pennsylvania, The Children’s Hospital of Philadelphia, Penn Presbyterian, and many health institutes like the Wistar Institute and the Penn Center for Aids Research are all right on Penn’s compact yet spacious, contiguous urban campus. There are a multitude of opportunities to be involved in Biomed research starting from your freshman year that will give you access to real, substantive, and meaningful research experience with one of the most well funded research universities in the world. And because of Penn’s One University Policy, undergraduates really do have access to this funding through their own projects and, more frequently, through the projects already established by faculty and grad students who are constantly looking for support and opportunities to mentor students. Penn’s Center for Undergraduate Research and Fellowships also does an outstanding job of connecting students to the research opportunities that work for their educations and schedules. It is a wonderfully supportive environment in which undergraduates are encouraged to partake in research at the highest levels.
I don’t know too much about Penn’s CS beyond the fact that it is well regarded and places its students in the jobs they want after graduation. Penn does host the largest collegiate hackathon (http://www.upenn.edu/pennnews/news/pennapps-brings-worlds-largest-collegiate-hackathon-wells-fargo-center-sept-4-6) and people seem to enjoy what they study.
Given that both will give you a great education in engineering I would focus your research on other qualities that are harder to conceptualize without a visit. Columbia is more urban and has a smaller campus (~40 acres compared to Penn’s ~300 acres). New York City is larger and has more of pretty much everything than Philly. Philly is smaller but also more intimate and Penn’s close proximity to the center of the city gives you greater access to Philly’s admittedly more limited (though not inferior) resources. Penn is considered to have a more pre-professional vibe. Penn is also the Social Ivy and is considered to have a more robust social scene than its Ivy peers. Greek Life is also more of a presence at Penn. When choosing between colleges, I chose Penn’s College of Arts & Sciences over Columbia College because the education, campus, city, and social life were better suited to my personality. Consider what you value in a college experience and go from there. You really can’t go wrong between the two of them!
One consideration, and that strictly from an academic perspective, are the course requirements for college of engineering students. Columbia has core curriculum requirements and Penn has sector requirements. These may or may not make a difference to you in the decision process of where to apply, but they might. So look into what courses are required (beyond the engineering courses).
Penn is a much more flexible institution. The engineering buildings at Penn are much nicer than those at Columbia, where the Mudd engineering building has many windowless classrooms. You’ll also get smaller large lecture classes at Penn like < 100 for physics and chemistry but not at Columbia. I also think ED is more of an edge at Penn than at Columbia.
However, OP should pick the one HE likes!
Really you can’t go wrong. Decide which environment and which curriculum you prefer.
I hope @PennCAS2014 is an ambassador for Penn because s/he made me want to go there, and I graduated from college almost 10 years ago lol.
I agree that you can’t really go wrong, but I will add that if you are interested in business classes Penn is going to be way better for that. They actually have undergraduate business classes there through world-class Wharton. Columbia undergraduates can take some business classes at GSB, but getting into those classes is very competitive - MBA and other business students obviously get first choice; there are only certain business classes open to undergrads, AND you are also competing with all of the other graduate students on campus who are also able to sign up for those classes if they want to (I was in public health but I could’ve taken a class at GSB if I wanted to).
There is a special undergraduate concentration in business management with classes designed for undergrads, but you have to apply and the program only accepts up to 30 sophomores and juniors.
I also don’t know how Penn’s campus is set up, but Columbia’s academic medical complex isn’t on the main campus - it’s on the Medical Center campus at 168th St. It’s only about a 20-minute subway ride away and there is a free shuttle bus that will take you between campuses, but that sometimes seems to be a barrier for some undergrads who’d like to do biomedically-related research uptown (but not all - a lot of undergrads do ride uptown to do that work).
You can’t go wrong with either and if you don’t have a clear first choice it probably doesn’t matter which one you ED to. But given all this information and what PennCAS2014 said, I’d lean towards EDing at Penn since it seems to have more precisely what you want.
@juillet haha thanks! I’m just a loyal alum but if Penn wanted to pay me for it one day down the road, I wouldn’t say no 
Also, all of Penn’s schools/institutes/etc., including the medical complex, are right on campus. The biomed library is actually right behind the most popular freshman dorm.
Have you visited each? I would decide based on the feel you get from each campus.
I would choose Penn, but that’s because my daughter loved it.
Both schools are great.
Actually, what @julliet said about GSB courses isn’t the whole picture. Columbia does have undergraduate business courses which are taught in the IEOR department in SEAS. However, they may have a slightly different emphasis than Wharton undergrad courses.
I still maintain that OP choose the one he likes. I am alum of both - undergrad/grad. The two cities, campuses and students are VERY different.