Ray Samuels B52 headphone amp as preamp?

I have one used as a headphone amp and it does sound nice as a preamp also (miss a remote volume control though, but I can live with that).

My question is, how does it compare soundwise to other good tube preamps? What am I missing vs. some of the better preamps mentioned here?

A review of the B52 when it came out said it compared well to his big VTL preamp.

Thanks.