PS Audio is a consumer based company, Benchmark is a professional based company - big plus for Benchmark. Paul McGown will retire someday and don't know what will happen to PS Audio. Owned a DirectStream Junior, service was very good, but they've gone into some odd directions in recent years, is run like Paul's pet hobby.
Trialed a Freya with nice NOS tubes in every possible configuration and didn't notice any change/improvement, even swapped the stock tubes back in. Blew one of the NOS tubes before sending it back. A tube preamp acts as a buffer to color the sound and change imaging, making everything that same color/image. Is that what you want?