I think AC Milan is always a uncomfortable opponent for teams like Barca, so it won't be a bed of roses for Barca
I like the AC Milan team very much... It doesn't consist of old players anymore like many other Italian clubs. There are great talents like Krkic, de Sciglio, el Sharaawy, great technical central midfielders like KPB and Montolivo... and now they have Balotelli as well. I love this mixture and imo it's a quiet amazing team. In the last month the results has been more and more consistent and they operating well together. Especially at home, I think they have good chances to reach at least a draw.
But surviving in Camp Nou? This mission might be unreachable.
It's a pity that teams like Ac Milan or Arsenal will be eliminated in round of last 16 while Gala or Schalke will reach the quarter final