Just received my new Digiface USB and hooked up for a quick check with headphones.
Because previous use of a Babyface, the actual driver is already installed.
I did nothing else than plugin the USB Cable.
USB Settings starts up as expected, the unit is recognized and locked by a click.
Totalmix starts up as expected and shows all INs and Outs, fantastic.
The Mac did not change his output, he thinks he is better than the Babyface.
Good bye onboard sound, Digiface is your master.
Play a musicfile and connecting the headphone to the socket.
Voila ! The music plays loud ! (headphone in hand !)
I did not touch anything in totalmix, Channel 1/2 is automatic on the headphone socket.
I have to reduce the output volume a bit, it was too loud for me.

Wonerful ! It works perfect from itself without any problem, I am writing here just for telling something positiv !

I will test adat connections later on. For the moment I trust to my experience with many RME devices, I expect the adat i/o's as working fine.
Greetings and big Thanks to RME for a very useful equipment.