I have the Peachtree Grand Integrated. I already owned an Audio Research VSi55 tube integrated, but living in Phoenix I wanted something that would run cooler during hot summer months when I didn't want heat from tubes to add to an already warm house so I bought the Peachtree intending to use it during the summer. I loved the sound so much, it has replaced the Audio Research in my main listening room. It runs cool, it sounds superb, and it's built every bit as solid as the Audio Research.
Going in, I expected the tube buffer to be a gimmick, but I actually use it more than I thought I would, when I want to take the edge off of poorly-recorded material.
I've run it through various speakers, and currently have Wilson Benesch Arcs and BMC Purevox and it's great with both.
I've never owned a Naim or Krell, so can't compare for you. I guess the best endorsement, other than that it sounds every bit as nice as the Audio Research, is to say that if something happened to the one I have I would buy another.