I have been using my EY miles on VA - availability is pretty wide open on many VA flights.
I am yet to understand how VA awards are made available to EY - as I can sometimes see seats on EY that are Tier 3 for Velocity and sometimes not bookable when only Tier 2 and 1 rewards are shown available for Velocity.
The booking process is really smooth since they switched to Amadeus - seat selection sticks to the booking - and is instant and in AUD - their payment processor seems to be based in Australia (no surcharges with Westpac & Amex).
It however now locks the EY FF number in the booking - unsure if VA can override it.
I could not retrieve my VA PNRs via MMB EY - had to retrieve them via EY's Twitter.
I have also changed one award - had to call the Guest Centre to do it - which then sends you a payment link (Amadeus standard payment link) - which allows you to pay with your Australian credit card directly.
The ticket was edited and re-issued instantly and correctly reflected on VA's MMB.
VA MMB still sees me as EY Plat whereas I am now EY Gold.
I assume it's relating to the extra two months of bonus status before I am properly shown as Gold.
I really enjoy the combo EY/VA - one of the better ones of VA/Velocity!