Multiple VMS Servers Against NVRs With Single VMS Server

We are working on a project where the customer is asking which is a better solution:

To use multiple VMS servers as a recording and management servers, against using single or dual management servers with multiple NVRs.

Can you advise the advantages and disadvantages of each solution.

Emad, can you cite specific brands the customer is looking to use? It's a little hard to discuss this abstractly.

I don't think the distinction being raised is as precise as the customer is making it seem to be.