I received my Opera about three weeks ago.
I am very impressed with the amp section (just as I expected) and quite surprised with the DAC performance which is, to my ears at least, on par with my NAD C542 and Arcam DiVA CD73.
The Opera was supposed to server as headphone amp in my secondary rig but in the end it became my main headphone amplifier, replacing both Ray Samuels Audio Emmeline II "The Raptor" and a fully modified Musical Fidelity X-CAN v3.
As to prons and cons... Well, just pros for me. I can't say I am dissatisfied with any portion of the Opera. It mates well with all of my headphones (AKG K701, Sennheiser HD650, Beyerdynamic DT990) and I think the main feature of this amp are its neutrality and the ability to let the signature of the headphones pass through. It doesn't add artificial brightness to lift the Sennheiser "veil", it doesn't emphasize bass impact to boost the K701's shy bass (apparently, the AKG K701 bass presentation is fine to me), etc.
It seems a lot of you complain about the gain setting... I think you might just be listening too loud. .) I keep mine on low gain (!).
So, a great amplifier indeed, in my opinion.
