Real Madrid, Manchester City and Bayern Munich are considered to be the most consistent and strongest teams in the Champions League this season. Although Real Madrid have some weaknesses in attack, Ancelotti continues to try his best to fix these weaknesses. And because of this, Real Madrid's performance is still very consistent. On the other hand Bayern Munich team is very strong. And I would say Munich have the strongest squad in the Champions League. Manchester City midfield is a bit weak. However, due to Guardiola's excellent match tactics, we are getting good performances from this team in every match. I personally don't see Barcelona as favorites for the Champions League anymore. The performance of this team is very erratic.
These three club are indeed the stronger candidate in the Champions League, not only this season but also the previous season, but if you look at it, it seem that Manchester City is trying hard to winner the Champions League title again this season like the previous season. We can not be sure which of the three club will win most deserved to wins the title because these three clubs are still performing strongs this season in the Champions League and have not suffered defeat so far.
Barcelona is not a strong candidate because its performance has not been completely stable so far, but Barcelona is still fighting hard for it, and is trying to get the best position in the Champions League even though it is not a strongst candidate to winner the title.