Hello
Thanks for using SupportForums
Here are some basic differences:
VDS = This is the a distributed switch provided by special VMware licensing. Can only do VLAN encapsulation. The APIC can send API calls to vCenter to create and manage the VDS
AVS = Individual 3rd party switch (very similar to the nexus 1000v). This is a Cisco proprietary switch designed to integrate with ACI. Can be VXLAN or VLAN encapsulation. Uses the API and Opflex to communicate to the fabric. AVS can also act like a FEX and forward traffic or send all traffic to the leaf for processing. AVS provides a lot of features specific to ACI.
Here is a good case study on this same question:
http://www.cisco.com/c/en/us/products/collateral/switches/application-virtual-switch/white-paper-c11-736554.html
As well as another SupportForum post on the same topic:
https://supportforums.cisco.com/discussion/12722436/cisco-avs-vs-vmware-dvs