Funnily enough, I have flown VS internationally since 2000, and exclusively so. The most complaints I've seen are MAN-MCO or LGW-MCO, or from LHR to JFK or LAX.
Every flight I've had with VS has been, on average, good. I flew with BA internationally once (as a 'refugee' after AF had to cancel my flight due to an ATC strike in France) and it was horrible. I felt like I was only barely tolerated.
My most recent flight on VS was sheer bliss, and I'm happy to fly VS again. :-)
In Europe I do prefer BA (probably because VS doesn't do regional).
:-)
S.