I honestly can't think of any good reason today why someone who could hack would want an MBA.
If you're concerned about learning, you will learn more about business in one good hands-on project than 2 years of formal education.
If you're concerned about having a mentor, you will meet much more business savvy people in business than you ever will in school.
If you're concerned about money, 2 years of earning will put you thousands of dollars ahead of 2 years of spending.
If you're concerned about what others think of your credentials, you're focusing on the wrong thing.
If you're concerned about climbing the corporate ladder more quickly, then fine. Get an MBA.
And, most of all:
If you're concerned about making yourself the best you could be, then build, build, build. You already excel at the weakest link in the business chain. You will get better by continuing to "do" in your specialty. More school will add little, cost time, cost money, but most of all, cost experience doing what you already love and what the world needs most right now.