Hi!
Well I'm at the end of week 3 of my training course and I'd say definitely BA! They're so professional, friendly, smart, well paid and excellent working conditions. I worked for 3 airlines before and BA is way ahead
I have friends at VS (one stil on training) and most give back negative comments about the airline.
However its what you want at the end of the day. As someone said a few messages above, Virgin is a good way of seeing the world short term. But for a career I'd say BA... as you're set up for life