M&A Advisory at Big 4 (need urgent response before offer deadline!)

Recently got offered an associate role at a Big 4 firm for M&A Advisory. This is in a relatively stable middle eastern country. They would start me at Associate 2 and fast track to Manager in 1,5 years which is a pretty good deal. Manager is akin to a VP in this group. I would be 27 by the time I'm an M&A manager so I guess it is somewhat impressive? Another very important thing to consider, the M&A role is unlike what big 4 does in the US which is due diligence and integration consulting. It is pretty much traditional investment banking. Because big 4 has a big footprint in this country and they were here first, they decided to directly compete with investment banks and are successful so far by deal volume.  

My background: US grad, worked in US 2.5 years for a mid-size corporation doing M&A and Corp Fin in general. Had to leave and go back to home country for personal reasons. Every interviewer in home country were impressed by my exposure and I can say the doors are wide open.

My question is: What kind of exit opps will I have? My plan is to get promotion, work manager for a year, come back to the US for a T10 MBA, and pursue either PE or Corp dev. But not sure how well this "M&A manager in another country, and although it is big 4 it was basically investment banking" narrative will translate. 

I hear horror stories about how US big 4 Pidgeon-holes you to accounting after Manager level. The FP&A and accounting is by far the LEAST favorite part of my job so that would be a nightmare. 

I appreciate your input.