Thanks for asking. I seldom post my modest opinions unless specifically requested to do so.
RCA outs to headphones.

Yup.. much preferred the tube output to my Schit Asgard. By big margin.
Cans = HE-4 and HE-6.
Compared to other DACS I have owned

I really like it. It reminds me of my Eastern Electric original DAC a lot.
Having multiple inputs and outputs puts the convenience factor through the roof for me.
And since I am feeding the DAC out to a Dodd tube buffered Sensation the warmth of the GF-11 presentation is considerable and very favorable to me as well as allowing me to use the tube output to my Asgard..
OK.. What have I compared to direct DAC to DAC?

Maverick D2.. I much prefer the fuller sound of the GF-11 over the lean D2.
Emotiva XDA-1.. much prefer the warmth of the GF-11 over the Emotiva which is a nice DAC but a bit to musical for me.
Schit Bifrost (non direct) Bifrost is a really good DAC but my slight preference for the less digital character of the GF-11 along with the multiple input/output convenience made it a really nice fit for me in my system.
Merry Christmas.
Tom