First, congratulations for being admitted to both. That said...

1. I was an undergraduate student at Stanford and the Ph.D program (experience) is vastly different than that of an undergrad so with that, take this bit with a grain of salt.

2. I've never been a Berkeley student so obviously my opinion is also skewed because of this so take this into account as well. If it helps, I'm a total geek, not into sports, and could care less for the school rivalries so at least that is not factored into my opinion here.

With those things said, I strongly believe both schools have a very strong CS and entrepreneurship presence and being admitted to both is a great accomplishment. However, having said that, I believe that Stanford has more going on. I might be a bit bias simply because I never got to be a Berkeley student (and I never applied either) but historically, Stanford is known to produce an amazing number of founders for some of Silicon Valley's largest companies (that isn't to say Berkeley doesn't have its wins). But at the same time, you have all the VCs here, it's at the heart of Silicon Valley, in a much better location (in my personal opinion), and ultimately many of the advisors/professors and people here (including guests) are VCs, CEOs, or other prominent figures.

I don't think you can really go wrong with either but if I had to do it over again, I'd still choose Stanford. For the record, while I didn't apply to Berkeley, it was in the back of my mind prior to applying to Stanford. After talking to friends, researching, etc... I chose Stanford and couldn't be happier.

Since you didn't mention it explicitly I will -- you also need to pay particular attention to the Intellectual Property Rights policies at each of the school's you are considering.

There's a much greater "propensity for entrepreneurship" at Stanford. It's right in the middle of Silicon Valley, which influences the students a lot (and the curriculum a little). Berkeley is much more on the periphery, and feels much more like a traditional research school.

Your advisor may be the biggest factor in the Ph.D experience. Unfortunately I don't think you can get that settled until after you matriculate. If you notice a big difference in the "management style" of the relevant faculty at the two schools, or don't think you could work well with some of them, listen to your gut. Don't underestimate how this will affect your quality-of-life and your output.

As gyardley said, be sure to investigate Ph.D stipends. Stanford's stipends seem quite generous, but my friends at Berkeley are frustrated with the money. (I think it's something like 30k vs. 20k at the two schools. Maybe not a big deal in the beginning, but if you've been there for 5 years and you're approaching 30 and still making 20k, it starts to grate on you.)

Stanford's campus is beautiful, but a bit isolated from the rest of Palo Alto, let alone other parts of the bay area. To get out of Palo Alto, you'll need a car, or a lot of patience for buses and trains. Berkeley feels more like a city campus and is more integrated with the rest of the city. Plus, BART goes there and that can get you to S.F. easily (although there's no easy way to get to the rest of Silicon Valley).

I'm a Stanford CS alum, so I'm a little biased, but they're both good schools. Congratulations on being accepted to both!

Eight years ago, I was a Ph.D. student in history at Stanford, and had a good friend who was a Ph.D. student in history at Berkeley.

Obviously, the situation may be different now, and different for computer science.

That said, for me and my situation the financial package at Stanford was far superior to the financial package at Berkeley -- more stipend for more years with less TA requirements.

If the same is true for you today, I'd be pretty biased towards Stanford.

Not familiar with the programs at either university, but consider that Stanford is one of the wealthiest private institutions in the world against the budget crisis that the state of California is currently facing. Financial security goes a long way in ensuring that you're in an environment conducive to working on your startup.

Congratulations on being admitted to both - it is a big achievement getting accepted from 2 of the most reputed CS schools in the world!

I've not attended any of the 2 but I'd prefer Stanford personally.

Can you please share how you got into both the programs - I mean your subject, experiences, past work, etc anything that might help a future aspirant?

This (current) thread might be of some help to you as well:

http://news.ycombinator.com/item?id=2267285

Stanford is closer to Sand Hill Road.

Steve Jobs gave the 2005 Commencement address there. He went briefly to Reed College in Portland. I don't believe that he ever matriculated at Stanford.

Agreed.