After several weeks into using the device I think it's time for a follow-up. The initial amp I received that I had detected some timing issues with became much worse the following day. It developed quite a bit of static and had volume adjustment issues. I worked with Ray on it, who was prompt and quick, and a bad capacitor was to blame. Since then, I've had it back for several weeks and it's been great to listen to. Sometimes little problems will pop up, but I'll reset the rig and things will be fine again. I can't directly fault the 71-B in these instances, because honestly it could be anything, including my going on 3 year old occasionally temperamental iphone. That will be replaced soon, but that's a whole other story.
I've used the 71B+HP-P1 rig now in car audio and a few home theater systems and it has been great for all of that. In fact, it has sounded significantly better than the other sources in most of these rigs based on my experience, but these were not high-end systems to begin with. I'm away from home now, but when I get back I'll have time to get my IEM cables re-terminated for balanced and try it out.