Right now I'm thinking of placing my bet on Dortmund cause those big odds could end up coming in for me, not like I feel that Dortmund could win either bayern or real Madrid but you know when ever a small team or rather least expected team gets to the final, the fairly tale story would most likely be finished with the taking the lead and winning the Cup, it's not to bad to place a stake in an unexpected event.
Betting on the weaker team will have higher odds if they win. It is worth placing a bet on this bet because Dortmund is very capable of creating a surprise in this year's Champion League. Most people bet and think that Real will win the cup this year, but in my opinion, the majority is often wrong. 
I also hope that this year Dortmund can do something surprising against Real, making this tournament more attractive, instead of just rotating the championship between a few teams, and Real is always among them, it's so boring.
Borussia Dortmund has a mixture of veteran and young players in the squad just like Real Madrid so I expect the both teams to produce exciting football in the game in order to keep fans entertained through out the course of the game. That game will be Marco Reus final game for the club as he'll leave the club at the end of the season so winning the UCL title will definitely be his biggest send forth package if you ask me
If compared in terms of squad, Dortmund cannot compare with Real in terms of young players. They are relying heavily on the performance of veterans like Hummels and Reus. The only young player that impresses me in Dortmund's squad is probably Nico Schlotterbeck. He has the ability to read the game well, is excellent in the air and has impressive tackles. Schlotterbeck is the perfect complement to Hummels. This duo makes Dortmund more solid and difficult to overcome in the upcoming final.