Given the code-sharing arrangement with VA & DL and the choice that one one can book either on DL metal or VA metal when flying from SYD-LAX, are there any reviews around that comp

Given the code-sharing arrangement with VA & DL and the choice that one one can book either on DL metal or VA metal when flying from SYD-LAX, are there any reviews around that compare the pros & cons of each airlines business class?

I can't speak to the DL service, as I've not flown it, but here's my review of the VA service SYD-LAX: http://www.ausbt.com.au/review-virgin-australia-v-australia-business-class-seat-sydney-los-angeles-lax – the meal service is excellent, as is the in-flight bar.

I'd say that VA is the best option for everything but the seat – VA's is a fairly basic fully-flat bed which lacks padding in important places. DL has a herringbone layout with direct aisle access for all seats (see http://www.ausbt.com.au/the-best-business-class-seats-from-australia-to-the-usa ).