It depends really on what you want to backup. We have SQL and other backup scripts running on VMs that backup to a central location (incidentally also a VM), then these are backed up to tape. The benefit of this is massive throughput because most of the work is done within the physical backplane (blade chassis).
If you want to backup your VMs and don't want to use VCB I'd suggest ESX Ranger. You don't need an NT VCB Proxy (that you then have to connect to the same storage group as your VM hosts... a bit of a risk), and you don't lose your hot backup option. You can get it from www.vizioncore.com .
We've set this up to a single location (our meta-lun on the SAN), these can run during the day, then the location is in your BEX selection list for backup later. We only use these for bare metal recovery scenarios though.
Hope this helps...
