Integrated tube amplifier - finest ?

I really don't have experience with all of the ones that you mention...but the one that I have owned...is superb, the VAC Avatar. It also has an excellent phono stage...worth the look and listen.

I owned the Bel Canto SetI40 and now own the Pathos Twin Towers. It is part of a second system. I have Lamm ML-1's in the main system. I had a cap mod done on the Pathos (slight opening up of the top end) and they give the Lamm's a real run for the money. I love the Lamms but as a value I have never heard anything close to the Pathos at any where near the price (and it is stunning visually). I have not heard the Viva but would assume it is very good as well.

The amps I have heard from this list are the Jadis Orchestra Reference and the Pathos Twin Towers. I cannot comment about the others, but feel you would be happy with any of these fine products. The Pathos is fabulous, but not the type of sound a tube lover is into. It is more open, detailed, and extended, while lacking the sweetness and warmth that we buy tubes for. Interesting the above post states he preferred the CJ CAV50 to the Jadis Orchestra(though he later states there was a problem with the Jadis). I feel just the opposite. I cannot find one area where the CJ is superior to a Jadis(unless you prefer a REALLY warm sound), but all of this is personal opinion. I own a Jadis Orchestra Reference, which I feel even much superior to the Orchestra. It is more like a DA-30, with passive preamp, and in my opinion should carry a different moniker to avoid confusion with the Orchestra.

I too heard the Mesa Tigris....I found it superior to the CAV-50 only with Rock and Roll loud and pumping...which I do not listen to.

I found the VAC Avatar to so profoundly change tonal color that I felt compared to measure its response (on an easy 4.5-9.5 ohm speaker load): compared to several SS amps, which mutually agreed well within the +-0.25 dB resolution of my meter, the Avatar...down 3dB at 250Hz climbing through 0 at 1kHz, then peaking at +3dB at 3-4kHz (ouch! went the horns!), then falling precipitously to -8dB at 10kHz! (no air wharsoever!), then recovering to +2db at 20kHz. The dealer verified that the amp was functioning normally, so I called VAC, who admitted that all EL34-based amps are colored tonally, and that I should try their more expensive separates for a neutral sound! Oy.... I ended up getting Aleph separates for an easy, but pricey, solution. From my experience I can imagine that the AVATAR may synergize well with a speaker that has complementary frequency response anomalies, like an overly warm lower mid, too-soft low treble, yet VERY hot high treble. OTOH, I'm not even aware of such a speaker design, but obviously some folks like what this amp does to their system...but neutral it ain't--not by a long shot! Subjective effect: male voices severely pinched, horns and strings VERY hard, cymbals & brushes extremely rolled off. I'm sorry if my criticism seems harsh, but this amp wasted a lot of my time. Happy hunting.