I think you should have only one vCenter in the main datacenter, but first you need to check the vCenter configuration maximums, because for example, if you have more than 1.000 hosts, you will need more than one vCenter.
Another point is if you're not in the main datacenter and lose connection to the main datacenter, you will not be able to manage your local VMware infrastructure from the vCenter, then if access to vCenter is critical to manage operations in non-main datacenter, then I will recommend a vCenter Server in each location and configure the Linked Mode between the vCenter Servers.
The image below shows the configuration maximums for vCenter Server 5.5:
http://www.vmware.com/pdf/vsphere5/r55/vsphere-55-configuration-maximums.pdf