I bought a new W4S STP-SE and ST1000 amp and probably have 100 to 125 hours on the units. They are running Maggie 1.7's with an AudioSpace CD8 as the source. I routinely play the Maggies at 40 to 50 on the volume control so I am staying in the passive mode.
The W4S units are plugged into a surge protector from Parts Express with no special cabling or power cords. The speaker wires are nothing special; the gauge is thicker than lamp cord.
The W4S have really opened up in terms of bass in the last few weeks compared to straight out of the box. The bass is articulate with texture and timbre. No boominess at all. I used palpable to describe the bass when I first heard the W4S in my house. I was wrong, it is palpable now. Thicker and richer.
The sound stage seems to come and go so I think that depends a lot on the specific CD or album. This is a piece of advice that I picked up on another Audiogon thread and I think that it is true.
The treble, to my ear, sounds good most of the time. On occasion it does seem a bit harsh. I would not call the treble "liquid" by any stretch of the imagination and I am not sure that that it is necessarily "smooth" all of the time. I do not often hear the "sheen" coming off cymbals. Perhaps this is the source; I am setting up a turntable so more to come on that score.