VMware has updated Vmware data recovery (vDR) to be more reliable with less quirks in their latest release 1.2 and vSphere 4.1. Now you can also have up to 10 vdr appliance per vcenter with 4.1.
Some best practices when using vDR are:
If your using cifs use a datastore that is 500gb or less. This could be increase if there is a good storage array that is presenting the cifs share.
100 vm guests are now a hard limit per vdr appliance.
Block change tracking is used for backup and restores. So the first backup is a synthetic full and the rest are based on block changes.
Using a vmdk as a destination in your vDR appliance for backup data provides faster backups and restores.
This is just a brain dump of some information I gathered from vmworld.