I haven't heard the Ni Vi Nu Connu LPs yet but will give them a listen.
Saw Butcher a bunch in the early 00s -- first in Chicago with Fred Lonberg-Holm and Glenn Kotche (didn't like Glenn's improvising at all [I dislike Wilco immensely] but Butcher was excellent) and subsequently in Texas solo, duo with Thomas Lehn, and in groups with the Austin New Music Co-op. All of the Texas shows were stupendous. It's been a while but I hope to have an opportunity to see him again.
I have a smattering of his CDs and those in which he deals most closely with resonance and acoustics have impressed me the most, but he's such an incredibly deep listener and gutsy player that even the "standard" recordings of post-SME interaction or the saxophone-drum duos with Prévost, Nilssen-Love, et al. are quite remarkable. The trio with Lehn and Shipp (and the duos w/ both) are really something else too, though of course I've recently been going back to them with a very close ear.