Honestly , Leverkusen is playing so smooth that I wouldn't be surprise to see them in the finals or even winning it because right now they seem to be one of the first candidates alongside Liverpool to win the trophy this year.
Meanwhile , Group B is fantastic to watch as you can't really tell for now who is going to advance beyond group stage

as AEK seems determined to qualify and leave Marseille out.
They've made a massive progress this season, not just this season, they did so last season. I don't them in this Competition next season.
What I'm not so sure of would be seeing Xabi Alonso with Bayern Leverkusen next season. Liverpool got so close a season to the finals but they couldn't get it. Sevilla displayed class during that finals.
I was rooting for Brighton, since it's the first time they've qualified for the Europa League Competition. But it's obvious they lack experience and chances of qualification slim.
What is so great about Brighton is how they are constantly working their way up in the Premier League and even though they don't yet stand a chance to qualify for the Champions League against the big teams, they are still able to cause the big names some serious trouble as we have seen a couple of times now.
There start into the Europa League hasn't been great, but there are still two games at home although both are relatively tough. There is Ajax Amsterdam waiting two times now. I think these two games are decisive. If they can win 4 points out of those two games, chances are good they can still make it.
Leverkusen is conquering the hearts from fans from anywhere. I think it is also because of Alonso as he is a very handsome guy with no prima donna behaviors or any stupid press conferences like Mourinho. He takes the time and answers in a nice manner. Great career in front of him and now we will see how far he can push Leverkusen.