I think City's style really doesn't suit Real, which is why I see them as favorites in this tie. Real will probably sit deep and wait for the counter attacks. If they open up, they will concede lots of goals because City is one of the best teams to exploit open spaces. This tie is imo around 70:30 in City's favour.
Arsenal vs Bayern is more difficult to predict because it can go both ways. Arsenal is in great form but lack the experience in this stage of the competition while Bayern will try their best to save their season in the CL. Bayern have a great team and if the players manage to step up their game, Arsenal will be in big trouble. I would say this tie is around 50:50.
Nevertheless, I'm looking forward to the matches. It's a pity that these matched are at the same time because I would prefer to watch them both.