First off, congrats on those acceptances! While I don't have any first hand experience with the programs, I nonetheless wanted to add to the above that Princeton does have an excellent Miltonist, Nigel Smith. On the other hand, I don't expect that Barbara Lewalski will be available to work with you at Harvard, considering that she is retired.
You should definitely take this opportunity to meet in person with both Gordon Teskey and Nigel Smith, and spend some time reading their books. Smith has a book called "Is Milton better than Shakespeare," which is really more for a popular audience, but you should also check out "Literature and Revolution in England." His work is quite historicist, while Teskey is more philosophical. It seems misguided to say that one is "better" than the other -- whose approach interests you more? And most important, make sure you get in touch with their current dissertation advisees. Are they doing projects you could see yourself doing? How do those students feel about the advising they've gotten?
Also, look outside of the English department. Princeton may not have so many early modernists on the English faculty, but there are more you might check out in comp lit, especially Leonard Barkan. He directed Gerard Passannante's dissertation (he's now a prof at Maryland), which was recently published as the book "The Lucretian Renassiance." You should read that -- I think it might give you a good sense of work coming out of Princeton.