Juventus is doing moderately in the competition, but the Italian league has also become much stronger at the top in recent years. Arsenal play attractive football, but United can also score high. We have very nice matches scheduled for the next round, but it is too soon to pass judgment on that now. When the teams have come out of the winter break, we can better estimate which teams are the favorites in the tournament. Barcelona wants to avoid last season's defeat against Frankfurt at all costs.
I don't know why you mentioned Juventus in your comment, is it for trophy purpose? Juventus club in this season is not in good form and the management of it is not also helping matters so I don't tip them to be contenders of any title starting from the Italian local League to the European level. They have to put their differences in order and get a new coach if possible in order to be able to contend for any trophy. Europa League this season has big names in it so there is no chance for Juventus.