All in all a good experience:
I arrived almost an hour too early at the consulate. They still let me go in right away. With the K1 I didnt even have to stand in the long line.
In the consulate it didn't take long at all. The consul asked me a few questions, didn't even want to see any of my additional pictures/proof of ongoing relationship and I was done in about 10 minutes. The interview was even in German.
It took me an hour and 15 minutes TOTAL (walking in until walking out).