I have flown all 3 types of ACFT and I can tell you that both the 340/330 are great acft, the 320 is different ACFT.
just A lesson in facts in 2002 a A340 had a unreliable speed problem on T/O
the ACFT landed normaly.
all I can say is what ever happen to those guys could have happen to any ACFT
you have to kwon that 7 minutes after AF 447 an iberia A340 flew the same route and an Other AF 330 was also on the same route all those ACFT got home with not a problem.
So before saying that airbus is better or worse then Boing, well for that I don't know all I kwon is that I will fly anywhere in my A330