Performance Implications of running multiple Virtual Servers using one base virtual disk?

I tried looking through old questions, but couldn't find one that hit this exact question.

In VmWare's documentation on Snapshots, they mention utilizing them for a "process tree" setup. This would allow spawning multiple VMs from a base .vmdk disk. The idea is that you create a base disk and then snapshot it. This creates a "differencing" disk that is used for any changes made to the VM. I've tested this by using the following steps:

1. Create a base VM with a new .vmdk file, and configure it as needed
2. Shut down the VM
3. Create a new VM and choose to use the existing .vmdk disk.
4. Before Powering on the new VM, take a snapshot of the new VM.
   • This will create a differencing disk in the folder with the new VM
   • The new VM will write any deviations from the base, to this new .vmdk file.
5. Power on the VM
6. Repeat Steps 4-5 for additional VMs

My thought is that this could save on the amount of disk space needed to run multiple VMs on shared storage (iSCSI SAN).

The Question:

I wanted to see if anyone has run this setup and what type of performance implications can be expected (additional disk I/O, memory, etc) or any other snafus to be aware of? Are there any situations where this would cause more issues than its worth?