The both teams have the chances of winning because they are both in a good condition now, but Real Madrid have the higher chances of making it due to the regular participation and it have become part of them, this alone creates fear in the mind of opponent when they are facing Real Madrid in champions league final, they have the experience and currently they are in their best form, but still i can predict this game, let wait for the time and see who comes out champion.
Real Madrid are always favourites to win the championship league and when they get to the finals, it is always difficult for any other team to defeat them. Real Madrid has a better squad and more experienced players therefore Dortmund are going to be playing the biggest match of their career. Real Madrid has a better and more experienced coach, everything is in favour of Real Madrid to win and it will be very surprising if Dortmund come out victorious but I would not say it can not happen because what determine if a teams is going to win is their determination on the football field. If Dortmund knowing that this might be their only chance to get the Champions League trophy and play with all their strength, they can pressure Real Madrid into accepting defeat because no team is above getting defeated.
I agree with you that Real Madrid has a better squad and more experienced players to win the UEFA Champions League trophy tonight, but I disagree with you in saying that Borussia Dortmund will play the biggest match of their career. This is not the first time Borussia Dortmund has gotten to this stage in the UEFA Champions League competition, so it is not the biggest match in their career. Have you forgotten the UEFA Champions League finals between Bayern Munich and Borussia Dortmund played some years ago? That year, no club would match the Bayern Munich squad in the UEFA Champions League competition, but they struggled to beat Borussia Dortmund 2-1 in the finals, thanks to Arjen Robben's late goal. This is not the first time Borussia Dortmund and Real Madrid have met in the UEFA Champions League competition. When Lewandowski was still playing for Borussia Dortmund, they had won Real Madrid 4-2 in the UEFA Champions League competition, and Cristiano Ronaldo was also playing at Real Madrid.