Hi,

The VS flight goes via Hong Kong ( on the A340-600) and the BA flight gores via SIN or BKK ( 747 or 777).
Unless you have BA gold or silver card ( or equivalent OW status) you will not be able to book a seat in advance unless on a full fare but on virgin you can book a seat.

The virgin seat does not recline fully as a seat but when you turn it over to form a bed ( or ask the cabin crew) the bed is longer/wider and IMHO better than BA.

You get PJ's on Virgin on the overnight routes.
There is an on board bar with bar stools on VS ( good to chat with the crew).

Some people complain about the VS food but I have not found it too bad and on a par with BA food ( you do get soup as a starter on VS but not on BA) but my last CW meal on BA was IMHO poor.

The VS clubhouse in LHR is excellent . BA uses T4 for the australian flights ( due to move to T3).

AVOD is available on VS ( very good) and on the BA 747-400 ( they will not start on the 777s until August ( there is one 777 flying with AVOD currently I think)

Both BA/VS are pretty good. Have not tried SQ ( some flights on the A380) or EK.

Regards

TBS