Deane,
I don't think that the 6000 has any significant "bugs", and has "at least the reliability level of the TSU2000". But then again, I'm not sure what you mean by the "usual" glitches in a 2000.
My Marantz 9200 still has a firmware bug involving jumps to the macro side - the workaround is easy however. The 6000 doesn't have this problem.
Jim L