Like everything in life, there are no guarantees. It would certainly open you up to more opportunities. It just depends on how you approach it, or whether or not the opportunity presents itself at the right time.
Some employers will fund the MBA education, and there is always a catch. I was lucky to have some of mine funded, but not all of it. There is a girl in my company who had her MBA completely funded, but she's locked in for a while with a heavy non-compete clause, and she did it way before me. Most in my cohort paid out of pocket and had no jobs.
