So I've had quite a few hours on 2 different Brooklyn DACs now.
The first unit I purchased brand new with the intention of it being my all in one portable-ish dac/amp. At the time I was listening to my Utopias with a balanced cable so I hooked up the Brooklyn to my Jotunheim with XLR and really ended up liking the sound signature. Alot. It really pulls quite a bit of detail out of the music compared to other DACs I have or previously had. Compared to my DAC3 it is almost neutral, but a bit more punchy, more dynamic. You can really hear a big difference with string instruments.
But then, I decided to listen to some of my other headphones, the TH-900s (low impedance) and SE846s (very low impedance). I plugged my SE846 directly to the Brooklyn and got an earful of hiss. I could also pick it up with the TH-900s. I couldn't be sure I could hear it with the Utopias, but if I was plugged in directly to the Brooklyn it was always on my mind and it drove me nuts just knowing it might be there. It is definitely an issue with the headphone amplifier because listening through the Jotunheim results in a perfectly silent background. Hiss aside, the bass is less pronounced when using the built in amp (but still represents well) and the mids are just ever so slightly recessed. I contacted the dealer and also Mytek but there was no fix for the hiss and I couldn't pay $2K with that much hiss on the amp so it went back.
A couple months later I was able to get another unit as part of a trade. I took a shot in the dark hoping the amp issue was isolated to the first unit, but, this current unit has the same headphone amp issue. I found that messing with the analog vs digital volume control setting does change the hiss a bit, but not much. I ended up getting the Brooklyn for a really good price in trade, and at that price I can live with its amp issue. Listening to my Utopias through the Jotumheim is my current favorite setup.