Over time is becoming more complex to shift from Big 4 + Accenture to MBB.
Switching from OW-RB-AP-A&M is easier, but getting tougher.
At Big4 + Accenture, problem-solving, communication, type of projects, speed of execution, challenges are so different to those you face at MBB that many MBB have noticed that people coming from Big 4 + Accenture take a lot of time to learn how to work the MBB-way.
In some real Tier-2 firms (OW, RB, AP, A&M) more than 50% of the senior people have some kind of MBB experience and that makes junior resources more aligned with MBB's requests.
The slowdown we have seen recently in the consulting hiring makes everything more complex.
The other thing to consider is that if you stay 2 years at Deloitte, to make an example, and you move to McKinsey, your seniority will be lost, and you'll have to start from entry-level. In my view, this should not be an issue, but you have to be aware of it.