If you are looking for serious computer science expertise, Boston is a great place to be. It's not the place to find cheap web developers, but if your start up needs CS Ph.D.s who can write code you'll be set. Most of the famous Boston start ups were fundamentally algorithm shops.
For what its worth, most of the MIT grads I know have either stayed around Boston or gone into academia. Cambridge, and then later Arlington, are great little towns and vastly different than California.
For what its worth, most of the MIT grads I know have either stayed around Boston or gone into academia. Cambridge, and then later Arlington, are great little towns and vastly different than California.