I don’t see the bookies favoring any team here if you ask me, the two clubs both Manchester city and Real Madrid are the best teams in Europe currently, and they deserve the top spot. You see this odds sometimes are not just a thing that anybody will sum up most of the time they usually involve computer calculations for things involving each squad depth, and seriously Manchester city have that squad to go all ahead.
Recent seasons, Real Madrid won many Champions League title and Manchester City is one of few teams that won Champions League title by beating Real Madrid a long the way to final match and trophy.
It makes sense for bookies to give best odds to Real Madrid, the current champions, and Manchester City, the champions two seasons ago, and they are both still very strong and competitive. In a new season, they will continue to play with high quality and with their experience in Champions League, they will be able to go very far there.
As for Real Madrid no one can deny their position, there are always the team to beat before you get to anything like winning the champions league, even Pep Guardiola once said that they are the favorites as long as they have not been knocked out, when Manchester city won it, it was them that they defeated, same with Chelsea year of triumph too.
Real Madrid in the last ten years, usually go very far in Champions League and if any team wan to go to semi final, final matches, they will need to beat Real Madrid. Real Madrid can not win Champions League in all seasons but they are holding the record and their players have natural confidence when playing in Champions League. By many factors, tradition, experience, confidence and quality of players and coach, they are one of hardest team to be beaten in Champions League.