Still, German dubbing is one of the finest dubbing worldwide. They try to be in sync with the time the lips are moving, they try to find the best translation that also fits most of the lip movement (like trying to use a word with an "o" in it, when the person forms an "o" with their lips) and often times they also come up with brilliant ways to make a joke work that only works in English by finding an appropiate one in German.
Of course, there's still plenty of stuff to complain about but it's really nitpicky considering the quality we get over here.
And there's also some ADR in the original versions as well. It's not always that obvious, but it's there too.
Nevertheless, it's a different experience to hear the voices being part of the whole "sound system" of a movie rather than having this feeling of the voices being detached from the rest.
And yeah, volume levels and sometimes accents or mumbling can be a real challenge when watching shows and movies in English - or in the language the movie was produced in. There are German movies and shows where you don't really get everything because some actors are hardly audible or the dialects are so thick, that you can't understand what they're saying.