My battery powered experience is with the Sutherland phono stage. It was in the home of a friend, where Harry Weisfeld of VPI brought it over. My friend purchased a Scout, and Harry brought over the rig he was going to HE2003 with - his flagship TT and Sutherland and Manley phono preamps.
A/Bing the Manley with the Sutherland, I at first found the Manley to be a bit too forward and strident. The Sutherland was on the opposite side of the spectrum. The Sutherland was incredibly rich and lush.
However, after getting my bearings, and also going back to the Manley, I felt that the Sutherland was incredibly off the mark from the way things actually sound. While I initially loved the richness, I realized it was smoothing over an incredible amount of detail and blunting the impact of the music.
In fact, my biggest complaint overall about this battery powered component, and one that I can absolutely not get over is the fact that it robbed the music of its impact and dynamics. I hear that is a common symptom of battery powered equipment, but I hope Twl contradicts it. When all was said and done, if I had to make a choice, I would go with the Manley, and would try to tame the sound a bit, probably through a different cartridge.
On the positive side, the battery powered gear had great, black backgrounds. The silence was quite impressive.
While I have been around a lot of Rowland gear, and really, really like it, I have not been around any that ran off the battery pack, so I am interested in hearing the impressions of those here with experience. I hear that moving to battery power really improves things