Rloggie, I owned the Steelhead for several years and, during that time, occasionally ran the Steelhead as a full-function preamp in addition to using it solely as a phono stage into a separate line-stage preamp. Whereas I regard the Steelhead as a world-class phono stage, I would characterize the line stage aspect of its performance as very competent but short of the performance of a SOTA line stage.
In my system, the Steelhead sounded more "tubey" than I prefer with bass that was a bit "wooly" and sound that was a bit less transparent and less extended at the frequency extremes than a first-class line stage.
So, in short, while I think the line stage in the Steelhead is very good, IMO you can improve on its performance significantly (and at significant cost) if you pair it with a first-class line stage.