Hey,
At the end of the day once you graduate from MBA your previous degree will not have much value. However just on the basis of an undergraduate degree it is tough to compare considering both the degrees are in different fields , there are people who have done a BTech and are unemployed just like there are people who have done a BBA and got placed at Deloitte. It depends on the quality of the candidate , your skill set and ability.

Of we talk about the same person whose level of intellect and grades are same then surely an MBA.

But what sometimes a btech grad can earn more than an mba if employed in a good company. So it matters from person to person and the company he gets employed by.
Also it depends on the college eg. If an IIT passed graduate is compared with a person who has done his mba from an avg b school then the chances are that the IITian will be getting a higher package.
Remember that your first degree will only matter until you get your first job following which your performance and abilities speak for themselves.
So it depends on the above factors.
Hope It helps.
Regards!