Netherlands isn't that impressive of a team, to be honest. Their defense is incredibly average. They have an incredible attack, but if we consider that van Persie usually plays really badly for the national team, and that half of their attacking players are injured half the season (Robben, van der Vaart, even van Persie sometimes), they can be beaten by Portugal and even Denmark. Besides, Portugal has been lucky the last times they've faced Netherlands. I find it amusing people keep saying it is a closed deal, some say it's not that interesting of a group, seeing as Germany and Netherlands will go through comfortably. Let's wait and see.
Germany, on the other hand, have an incredible squad, with amazing goal scorers (Gomez, Podolski), great players in the midfield, attacking or deffending (Özil, Khedira, Schweinsteiger, Müller), a solid defense and probably one of the best keepers in the world. Plus, they all play in the same league and they have simply the best collective besides Spain.