Chris Evans of Architecting IT comments:

The discussion (although I haven’t listened to the podcast) revolves around VSA (a virtual storage appliance) that can run in a VM versus technology such as VMware’s Virtual SAN (VSAN), which runs in vSphere ESXi but is more tightly integrated with the hypervisor.  As Nigel points out, a VSA is more flexible in terms of being (potentially) portable between hypervisors, whereas VSAN creates a form of lock-in for the user.  Whilst that is true, I think however there is a wider discussion here that isn’t being explored and as usual it takes the customer back to one of risk versus cost.

Chris has a good breakdown of VSA and VSAN here. The answer varies based on what you’re trying to do. IT isn’t like a pair of sweatpants. One size does not fit all.

Read more at: VSAN, VSA or Dedicated Array?