After watching latest series of Grand Derbies I must say I'm not at all impressed by Barcelona, and also let me add I have the same opinion about Real.
When you look at their game you see 80 minutes of trying to get a faul and yellow or red card for any opponent. Great example for that is the Pepe - Dani Alves case. It was obvious on replays that Pepe did not touch him. And how Alves could have pretended like this acting such a pain etc. I mean Pepe did commit a foul there as it was a dangerous play and he deserved a yellow card, but after a good show from Alves and he got red one.
For me both teams focused more on acting than playing football in every single Grand Derbi they played. And this kind of big games are ones when you see if the team is great or not.
It's sad to say but they didn't win the big games in football game but in a TV dramma so they can't be called best team ever. Maybe just best team nowadays in current football realities.