the likelihood of being hired from a specific office is related to demand and supply for that office.
The demand side is related to the need for consultants and it is seasonal, meaning some years some offices hire more. When that’s the case, it is generally easier to get offers. A recent example is the offices in the Middle East.
The supply side is related to how many applicants apply to a particular office. From that point of view, New York and London are probably the most competitive in the US and Europe respectively.