Veeam Server with Vcenter / ESXI host.

[cag]

Are there any advantages / Dis advantages connecting to vmware as a ESXI host or via Vcenter.

The only thing I have notices that I cannot VSS servers when I connect to Vcenter but works if I add the servers as ESXI hosts.

[Gostev]

The advantage is keeping unique VM ID as VM moves between hosts, so that this does not affect backup jobs which "remember" VMs by their unique IDs.
Another advantage is that you do not have to go change Veeam Backup configuration as you add/remove your hosts.

The disadvantage is that vCenter becomes single point of failure, if it is down then no backups can be created.

This is it, pretty much.

[MCScrapE]

Along the line of thought using vCenter to be the source of backups instead of hosts. What if I had setup independent jobs for each VM and I want to convert to a single job? Will that cause problems with the existing backup files already on my backup medium?

[Gostev]

No, it will not cause any problems with the existing files, as each job writes into its own backup file.