Finally I had the chance to compare the halide bridge against an (un-modified) hiface, thanks to an Italian mate.
It took me about 10 minutes to see the differences between these two interfaces, using a reference recording (a Mozart violin concert, published by Pentatone). Dac is the Audio-GD Reference, connected to the Audio-GD Roc, driving a pair of HE-5LE.
I'm using Pure Music 1.6, with Hog mode set to 44.1
The hiface sounds airy, with a deep soundstage. The signature is brighter, with a sort of "wow effect", and all the details in your face. But it's artificial IMHO: string and horns sound way too loud and tend to cover the soloist. Horns particularly tend to "resonate" in a very weird way.
Dynamic passages are compressed, the scene gets congested, and this reminds me the sound using the toslink into the DAC.
The bridge sounds natural, the instruments are perfectly positioned on the stage, which is wider, close your eyes and you can touch them.
High frequencies are less grainy, and well controlled.
IMHO, the bridge is simply in a different league, period.