I had wriiten a post, #VDI Tip 69: Use QofS – UCS and VMware View 5 but it’s misleading. The premise of using QofS is still a good and should be done. Since VM-FEX is dependent on the number of PCI-devices that your server can handle. Since you can only have 32 PCI-devices per server and some are taken up my various functions, the Max is really 30 desktops. The report mentions 30 desktops being used for testing but never declared it as a limiting factor. I declare this report as Bogus!
If you want to run QofS with VDI you will need a Nexus 1000v or use the virtual distributed switch(vDS) and run the QofS from the vDS. If your running VDI with 30 VM’s or less per server, you work for a hardware vendor