I had the Isabella (including the Dac), and now the Weiss Dac2 with Amarra.
I prefer the Weiss/Amarra. It is very resolving, yet warm and liquid - so natural, just feels right. RWA Isabella is very good too, but trades resolution for warmth. Not the Weiss: it does both. No need for a pre-amplifier either, so compared to Isabella with Dac even pricewise better (inclduing Amarra at 1K).