We tend to switch between Virgin and BA dependent on price. In my experience BA are the better operator: Cabin Crew appear more mature and attentive; far less likely to have delays; Food (though bad) slightly more edible; better entertainment system (Virgin's always appears to break down); aeroplanes appear cleaner and better maintained.
All these are "marginals" though and as I said, for me the price tends to swing it eg:
2 years ago for 3 tickets BA were £200 cheaper so we flew BA (they also gave us a free upgrade for booking early)
Last year Virgin were £100 cheaper so we flew them
This year 3 tickets at BA were £1550 against Virgin's £2000, so yes, you've guessed it, we're flying BA this year