Mahbub

I have read the two threads in this forum on related subject. Since they are quite old (5yr and 1yr respectively) and does not relate to my problem directly, I decided to post it. I have a MS in Mechanical Engineering specialized in Computer Aided Design (CAD). Currently, I am working as a Software Developer in a CAD company. However, since my degree is in Mechanical Engineering as opposed to Computer Science I don't think I am getting the right amount of traction from it. Moreover, I always wanted to go for entrepreneurship or lead innovative projects in a company. On the other hand, I like research, but would like to do so in company to produce real products. Now, the question is which way should I go? PhD in Computer Science? or MBA in Engineering Management? I know, at the end of the day the decision is mine. But any advice, experience or thoughts will be appreciated.