The rates are pretty crappy, especially if you are flying on VA and connecting to VX for a domestic add-on. We're talking 100,000 points for ORD-LAX and 150,000 for JFK-LAX. Pretty ridiculous.
The 35K UC award from the east coast to LHR isn't bad, though the $1100 "taxes and fees" component is pretty brutal. Even worse is the $650 in fees on the 15K award. With the base fares as low as $100-150 round trip paying the 15K points just to save that is a really bad idea.
On the plus side, the entire redemption chart - all 1400ish rows of data - is available as a single XML file from the VX website. That made the analysis pretty easy.
More details on the rates and some of the quirks in the charts can be found here.
ETA: Looks like you can go the VS route from JFK-LHR-SYD by combining two awards. It would book at 120K points + $2100 in fees versus the VA option of 230K + $850. Both mostly suck.