Best choice pre-MBA: Uber or Unicorn

Hello, I am Brazilian and I have the goal to pursue a top-tier MBA in the United States. Overall career goal has been to try a Tech company in San Francisco.

I had a two year consulting experience in a tier 2 global Strategy Consulting firm, in Brazil the internship for these companies usually take one whole year, so I made my way from intern to second year associate (2 years ).

After the time in Management Consulting I made a shift to a huge local Latin American tech player as Strat & Ops, the experience was terrible, specially because of culture fit... In the end I had to leave the company after my area changed scope and they tried to force me to shift to another area. I've had a three months gap between the day I left the company and the day I received good offers, during that gap I did a lot of voluntary work for a LGBTI+ NGO and some courses.

Currently I have two offer in my hands, both for Strat&Ops Manager. One is for Uber and the other is for a very promissing latin american Unicorn.

So, what do you guys think? Should I join Uber or should I try an Unicorn before applying for the MBA?