I've had the pleasure of owning some really great integrated amps, including the VAC Phi Beta. My favorite though, has been the New Audio Frontiers 845 SE, which I regrettably sold, as my Reynaud Offrandes were not completely SET compatible.
Currently, I'm enjoying a humble Eico HF-81 with my Green Mountain Audio EOS HDs. While not as sonically spectacular as the 845 SE, it is totally non-fatiguing, and possibly the most musical sounding amp that I have had come through my system (there have been dozens).
Coincidentally, I have the Eico with Sam Kim at present, awaiting modification. I had a soft popping sound in one channel, which I suspected may have been due to a bad cap. Sam strongly recommended a modification to his 7 wpc triode design, as with your Heathkit amp. I was at first reluctant, but on the strength of his explanations, as well as the few rave reviews I have been able to find, we're going to give it a try. I'll know if I have a new king of the hill in about 6 weeks.