I do agree that there is no weak team or strong team at this level. When you are at quarter finals, all teams deserved to be there, and yes normally there could be some smaller teams here, but this time there aren't any neither, the lowest ranked team is Dortmund, which should tell you how strong this quarter finals line up of teams are.
I believe that it is going to be very fun to watch them all, every team has someone their strength to battle it out and I think that means a lot of games to watch and have fun. I will definitely be live watching City Vs Madrid game because that is by far the best match up of the season so far and I believe that we are going to end up with something much better eventually if given enough chance.
The team that has qualified for the quarter-finals is the best team, whatever they have been through, what is certain is that the team that got here is the best of the opponents they have eliminated.
A slight difference is normal but not excessive so that any team will not be too favored or there will be no team that is easy to predict to qualify for the semifinals.
All the matches in the quarter-finals will be interesting and fierce and indeed the match between Manchester City vs Madrid is a little different in terms of prestige or tension because these two teams were previously favorites to win the UCL this season but have met before and that happened yesterday. This season makes the battle in the quarter-finals this season even more interesting.