Hey there,
I was facing this exact same choice a few years ago between an MBB firm and MD in the UK. While many will say MBB all the way (and I don't necessarily disagree), I do want share some thoughts that might help:
1. MBB offices in Dubai are pretty well known for having a slightly “tougher” culture than other locations (your experience may vary, of course, but just something to keep in mind)
2. Will you be in a pre-MBA role at the MBB firm? There is a pretty big difference in salary between an Analyst & Associate (post-MBA) but you may benefit from the tax-free situation in Dubai
3. I would consider the role as well. Are you a generalist in both roles? Are they both similar in terms of clients, access to senior stakeholders etc.?
Overall, I think yes MBB is probably the choice that will present you with the widest opportunities in the long-term. That being said, Tier 2 includes many different firms and some compete strongly with MBB on things like comp, clients, promotion etc.
Feel free to DM me if you want to discuss the actual firms in question.
But regardless, you're in a great spot with 2 solid offers! Best of luck with everything.
Nauman