I'm an Afrikaans native speaker, so I approached the languages from a bit of a different angle. However, I'd say German is more difficult to learn in terms of linguistic structure and vocabulary, especially with the case system that meh mentioned, while the pronunciation in Dutch is a bit trickier. In essence, if you can gargle, roll your r's and spit, you can speak German. With Dutch it's a bit more melodic.
Very well put! I'm not a native speaker in any way. I took German in throughout all of high school and have a friend from the Netherlands and we were just about able to understand one another.