Berkeley:
+ proximity to SF
+ stellar reputation
+ well connected in the valley
- size of college/classes
- public (less funding)
UPenn:
+ Ivy League reputation
+ Can take Wharton classes
+ Private
+ More social? (subjective)
- Not as good for CS
Coming out of Berkeley you'd have more access to SV given that a lot of people will choose to stick around in CA. I don't think it'd make a difference either way as they are both good schools. Everything else depends on you. Study hard at either schools and BigCos will want to hire you if you participate in their recruitment process and ace the interviews.
Here is a different perspective. Figure out why you want to choose one school over another. If it is purely for vanity, go to UPenn/Berkeley and transfer to Harvard. If it is for learning, either are good enough, the rest is up to you. If you want to work in SV Berkeley buys you better access + larger network that end up working in Tech.
Anyways you should read this article [1] by Derek Sivers, I wish I had when I was going to college. If you want to get the most out of college, here is my advice: kill it in your academics; join a fraternity/sorority that you'd rank as the top three on campus; learn outside the classroom on your own; join a max of 3 clubs and get deeply involved (sky diving club, salsa dancing, etc); join a public speaking club; make lots of friends your freshman year, become the initiator of campus outings/group outings. I didn't do a lot of these myself, but if I could go back, these are some things that I wish I had done [Georgia Tech 2012].
* If you're a freshman you're likely going to change your major a few times. I don't know about UPenn, but unless things have changed EECS (and a few other majors/schools like Econ) is an "impacted" major, which means you need to apply for it once your preparatory classes are done.
* Start networking and trying to figure out what sorts of jobs you want to do sooner rather than later. I ended up doing programming after a somewhat circuitous job hunt the summer I graduated, but it could have been shorter had I started interning my last semester.
* Money is a real thing. Compare your financial aid packages and try and get a feel for the cost of living. If you're not a California resident, UC is incredibly expensive.
* Take advantage of the free/cheap things you get while in school. In particular, I wish I would have made more use of the gym/pools.
* College is a good time to start working on developing a good work/life balance. It seems obvious to me now, but schedule your classes in a way that's conducive to how you want to live. Don't kill yourself taking 3 really hard classes in one semester.
* Get involved in things you're actually interested in. It seemed like there were a lot of clubs in school that were basically shell games for "leadership" positions.
FWIW I transferred to Cal from community college. In my experience the instruction was, for the most part, the same quality-wise, but the classes were much smaller. I also ended up keeping a bit of a network from my community college, because there tends to cohorts of students that transfer to the same places.
I was at Penn recently as a grad student, and I joined with a Wharton MBA student to do a startup. Wharton provides a lot of resources, even for undergrads. We participated in Wharton's Venture Initiation Program (VIP) here:
http://vip.wharton.upenn.edu/default.aspx
That's a great program, where you'll learn a ton even if your startup goes nowhere. DreamIt is also in Philly, and a lot of VIP companies seem to get in.
My understanding is that Penn CS grads can expect high salaries right at graduation, so the hardest part might be fighting off the Whartonites who want you to code for equity. There is even a website about that. . . . But I'm sure Berkeley grads command high salaries too. At Penn I think a lot of CS folks go into banking because of the proximity to New York. Something to research if that's interesting to you.
If you're into security, Matt Blaze is at Penn. But again, hard to believe Berkeley doesn't have similar experts. Penn CS is also known for an interest in type safety, so OCaml and Haskell are big there. That specialization may matter more to grad students though. All the VIP companies I knew were using Ruby, PHP, or Python.
Make sure you visit both campuses and their cities. Personally Philly made me pretty unhappy and I was glad to leave. The city's attitude (not necessarily the school's) felt dirty, grasping, corrupt, and pitiless. But grad students are exposed to that more than undergrads.
Whatever you choose, best of luck to you!
+ Where do you want to live for the next four years?
+ Are you ok with the possibility of being a small fish in a small pond - more likely at Penn just because it's smaller and more elite.
Accessing SV and Wharton are things that few freshman are really cut out to do, SV because it requires execution and Wharton by design because it's a graduate school.
My advice is to assume that your experience doesn't position you to make an informed choice because there is a quantum gap between the preparation provided by secondary education and actual experience of university life with the possible exception of academics (and there still is a gap and all the other differences can exacerbate it).
Good luck.
If you think you might switch to business, then pick Wharton because it is one of the three elite business schools (Harvard, Stanford, Wharton).