I have the same intent - to relocate to whichever country I end up doing my MBA at.
I went to middle school, high school, and college in the States, so naturally, it was my first choice. However, upon researching all the H1B issues, I decided against it. Basically, you have to leave your future up to the luck of a draw in H1B lottery. Although the chances are not exactly low, I just could not take the risk. You get to enter the lottery twice, and in each drawing, you have about 30% chance of being selected. Using probability calculations, that works out to be 51% chance. Whether you take this chance or not is up to you.
You also have to consider the chances of being offered a job. A lot of American companies are reluctant to hire internationals due to the high chance of not being able to keep them after one year. Having to let employees go after one year is a huge setback to these companies. Therefore, you have an uphill battle to begin with. And then there is the issue of Green Card processing times. While your Green Card is under process, you are extremely limited in job changes, in both job position and employer. There seems to be a huge delay in Green Card processing times at the moment, and it can take years before you get yours.
Due to these reasons, I chose to go with a more secure option, which is Canada, although the average post-MBA salaries are lower compared to the US. After graduating from a 2-year MBA program, you are given a 3-year post graduation work permit, which is an open work permit that lets you work anywhere in Canada. There are also many options for applying for permanent residency, and you will most likely be able to file your application after 1 year of having full-time work experience under your belt.
It is ultimately up to you to decide which option suits you the best. I would like to advise you to do a lot of research and make a well-educated decision.
Best of luck!