Yes, it's the same unit. Only differences I've found are three -- 1) the faceplate (the Integra is more stylized, and has more control buttons visible on the front; Onkyo hides the control buttons behind a drop-down plate, but is boxier look); 2) the SC5508 has a "Pure Audio" mode that disables some other circuitry on command when playing some analog inputs; 3) the Onkyo comes with a 2-year warranty, while the Integra comes with a 3-year warranty.

I was able to negotiate a better price on the Integra with my local dealer than I could find on the Onkyo. And I like the more stylized faceplate.