Both degrees offer different skill sets and opportunities. An MBA is a universally recognized degree, and typically gives a deeper business grounding and opens up a wide variety of career paths. In contrast, MCA is a specialized degree which opens, to a certain extent, careers in IT.
Ultimately how you succeed depends on where your true interests are and what you really want to do. In general, as a brand an MBA is a much stronger degree. But then again, it depends on where you get your MBA from.