When we went in September 2010, a couple of our party upgraded to the BA world traveller plus.
In my opinion, the Virgin cabin is far superior. Much more luxurious feel, the mood lighting works really nicely and if there's only a couple of you, you may even get to go in the Premium Economy section, but on the top deck next to first class - therefore no kids around etc!
If you decide to travel with BA, we found the standard economy seats to be very good. Plenty of room to stretch out and unless you are very big, I wouldn't see the need of the extra width in the seats.
In terms of food, it was pretty standard airline fare, but the World Traveller Plus wasn't a huge step up.
I know that when we next go, we will try to go Virgin in Premium Economy. If we end up going with BA, then we'll definitely save the money and go in Economy as there isn't too much of a difference.