I had a similar situation last year as well. Received an invitation email from cx for initial interview half way through my master, I decided to prospopne the interview until I graduate, which would be in mid 2012. (I.e. NOW!)
The choice was relate very simple. The MBA you are doing now is about to finish, meaning that you almost got this one in hand. On the other hand, although the chance of having an interview is tempting, but it will be available again next year, or even sooner. I think it will be a better choice to finish off the master, and then proceed to the next interview slot, whenever it maybe, it will be there's waiting for you.
Besides, you will have a safety net ( a MBA) even if all things goes wrong (touch wood).
