Remarkable, transparent, bright, trivial to use, excellent build quality. What more could you ask for? The LEDs associated with the buttons (48V, Phase, -20dB, and Ribbon Mic) are ultra-readable, even in full light. The 2 buttons allowing gain adjustment are notched, and the coupling between the channels is perfect (within 0.1 dB).

Grace Design true to its reputation, no bad surprises. Obviously nearly €2000 for 2 preamps, it's not cheap, but the quality is there.