With the TosLink connection, I think the differences between the two processors became more apparent: the Grace was detailed and crisp, the HeadRoom big and warm.
I don't want to sink to the old analytical vs musical cliché, because it wasn't that clear-cut. I enjoyed and heard deep, deep into music through the Grace, but it wasn't particularly seductive. Well, gee—it is designed to be an analytical tool for recording engineers, and it shares certain characteristics with other products we audiophiles have borrowed from the pro world, including Wilson Audio Specialties' original WATT/Puppy loudspeakers.
In other words, I felt the Grace m902 was better at letting me hear differences between choices than it was at sucking me deep into performances.