Tough draw, but could have been worse. At least the travel will be as easy as possible.
Atleti plays Barca super tough in the midfield. Barca has not proven it can beat this opponent. Atleti might has a playing style that matches up well with Barca, they might have the best coach, they might be the best conditioned, they consistently play extremely hard and true to their style. Is their squad as talented as the bigger clubs? On paper, no, but this is not something that Atleti lets psych them out. At least Barca will not underestimate this opponent, they know exactly what a fine team this is.
This is a great matchup for the world to watch, and it clearly could go either way. I think Barca is back to fine form again, which should provide the edge for this tie. Now, if Neymar could just find the net a few times in the next three games, that is what needs to develop now.