Either on a resume is just saying, "Hey look, I have a bit more education than the next guy in the pile!" - and little else. It can be a marginal advantage there, but the effect is often negligible compared to networking.
What's more important is acquiring skills and experience. Do you want to learn more advanced CS theory, or do you want to start learning business theory? Keep in mind that you can choose one and still take classes from the other.
Also keep in mind that an MBA is really intended for corporate middle management. If that's the job you want, go for it. If you're more interested in startupville like much of the population of HN, then pursuing practical experience with product launches and building a business may be a more efficient use of your time.