Best Integrated, period.

With the same proviso, no such thing as best, I suspect the Vac Phi beta would be best in most circumstaces. Meaning it's output of 110 watts I believe, would drive most speakers. Having had a few very good integrated amps, Lavardin IT, Karan K180, clearly the best in my system was the Viva Solista. At 22watts, clearly, it won't be best in many systems.
Others I might mention, the newish Pass labs 150 integrated and Conrad johnson C200. Not much experience of them, but the companies products are always good, in my view

Another contender might be the LSA series hybrids. All have the same structure and put out 150watts. The Signature and statement have slightly different circuits and improved components. I have heard the basic reference version when it was DK designs, the other 2 are supposed to be a big step up. The basic one was very good indeed. Strong support from Bound for Sound and Stereo Mojo too.

Having gone through the thread again, I agree there are hardly any integrated amps not included. Power costs money, so the key to getting excellent quality in a cheap integrated, is how much you need. This applies to tubes particularly, but also Solid state, if you want some Class A bias. For me, the only thing making Solid State listenable, is Class A.
I have owned and used a lot of Integrated amps in the last 8 years, Viva Solista, Lavardin IT, Karan K180, Unison Research S6 and now the Pathos Inpol. Of all of them, the Viva and Pathos Inpol were the best, with the Lavardin a very creditable runner up. If I had to choose between them I would choose the Inpol over the Viva, just and with my current speakers.
Money no object, I think it would be the Darzeel, so transparent, fast and detailed, but not a hint of grain and harshness, a wonderful amp. I think I could live with any Ayon amp too. If I had to choose, it would probably be the SET mercury or crossfire.

I agree with you Keiseeg, about Jadis. It is just that they are so expensive, for what they are. Here in the UK, the DA88S was about £6500, a few years ago, now the importer lists it nearer £12000. It is very good, but not £12000 good. The answer is to look second hand I suppose

Having owned quite a few integrated amps and listened to many more, I have to agree with USB, the dartzeel is pretty remarkable, lightning fast, but smooth and detailed. If I could only afford it, I'll just have to wait a few years till one comes up second hand. Why would anyone sell one?

Just goes to show, I tried out a Unison Research S6, not the SE version and I thought it was frankly poor, dull, lacking in detail, dynamics. All these opinions are system, particularly speaker dependent and ear of course.

I still say, I have heard nothing to match the Dartzeel integrated. I had a chance to hear the Devaliet amp recently, with the Dartzeel next door. It's an amp that is flavour of the month at the moment. Yes it was good, the Dartzeel clearly better.