Napoli and Barcelona this season do not look as good as they did last season, but as we remember, Barcelona in the last Champions League could not even get out of the group, this season they were more lucky with their opponents, but now they are weaker, so compare them with Arsenal is difficult. Porto remains a dark horse, but I would still classify them as a strong middle team rather than a top club.
Current performance in domestic league, I think Barcelona have better performance than Napoli with their standings out from top fourth position, actually not easy for predicting who will settle one place to quarter final phase between Barcelona or Napoli regarding both teams can't consistent on every match. First time for Barcelona success qualify to round of 16 after failure in last two season and pressure for Xavi Hernandez how to make Barcelona glory for their performance in Champion League.
For Napoli, they have quit well performance in Champion League success lead until quarter final round but how their chance for this season against Barcelona on round of 16 will be success or have eliminated early their appearance in Champion League. Based on my opinion, I think Barcelona have bigger chance than Napoli but still waiting with Walter Mazzari will make new transfer on January or Barcelona have planning sign new players and make their performance more solid in Champion League round of 16.