I have a Corda Headfive so I can compare to that; sold my Grado RA-1 along with my RS-1s to pay for the new gear.
So far way too good; I'll further evaluate my new toys once I've played with them a bit. I can't wait to try other 'phones, too - I kept my Cardas-recabled Beyer DT880 and Cardas HD650... too much fun for me.
My guess would be that it's considerably more fun sounding, with a better power section than either (for better extension, dynamics, and control), and with a slight tubey warmth. When I listened to it, it didn't sound reference at all, and the sales rep agreed. Kind of an odd category of sound for a headphone amp but I enjoyed it. It was the kind of amp that just allowed me to enjoy myself without getting too thoughtful or analytical about what I was listening to.