I haven't tried VA but in the case of QF I do not believe the business class product is that much better than the economy product and the premium economy product is only marginally better than the economy product.
So at the price point that is charged I do not think it is worth it. Well not for me anyway. I have no problem sleeping in economy and I seem to be able to tolerate economy more than most people I know.
Have you been in all Three JohnK? There's a vast difference from a Y seat to a Skybed Mk II. One's a lie flat bed with a lot of pitch, the other is not. The Y+ seat is like the trans-tasman J seats. It's really very comfortable.