Are Pass Labs amps probably the best ever you can buy ?

Why complicate things? The answer is “yes.”

Checkout Michael Lavorgna's product of the year for 2018 on twitteringmachines.com

Its an amp that was released in 2005 and is very reasonably priced compared to some of the other amps you've mentioned. They are hand made to order and there is almost no advertising about them aside from when they were released over a decade ago.

Choose wisely.

Just love my SIT-1s.

COUPLE OF comments- A Pass integrated amp (and many others) do not come with fixed outputs. If you have a tape/ digital recorder it's not a good choice. Pass XA amps run VERY hot. Pass ALEPH amps run VERY hot. Some of their amps must be switched on by reaching BEHIND the amplifier. This can be extremely inconvenient in some set-ups impossible. The newer faceplates are much nicer looking than the previous design which was a total waste of aluminum and money (IMO).
The BIAS METER is completely unnessesary but it's still something you must pay for.  The wing style speaker connectors may interfere with tightening large cables. The old 5-in-one connectors were EASY to use.
(this goes for Levinson and Krell owners also). I like Rowland gear also and it runs cool. But it's expensive and the fancy "diamond cut" faceplates are easy to scratch up. But a friend has Aleph 1.2 mono blocks and although they are "not as good" as the new stuff, but OMG are they great sounding. I would NEVER recommend that he sell them.
But he did have to buy a remote switching unit because the power switches are on the back panel and hard to access. High end audio is a pain in the "neck".

Always interesting when someone tries to claim “best”.  I agree with a number of the previous comments, especially that it is all about system synergy.  Pass Labs build quality and customer service are legendary. I have recently auditioned a large number of amps trying to find the “right fit” for my system and my biases.  These included a Dennis Had Fire-Bottle, ARC, SIT-3, Bedini, F6, Sunfire, Counterpoint, BEL and Coincident. Before I go further let me say I’m all vinyl with an Aesthetix IO sig front end, a “Truth” passive pre and VSA speakers. For me, in this kit, the 211/300b based Coincident Dragon MKll’s are sublime, followed surprisingly closely by 40+ year old class A SS Bedini’s.  
Unfortunately, it is very expensive and time-consuming to audition amps.  I would say don’t hurry and get 30 day Right Of Returns, even if you have to pay a restocking fee.  Fortunately, a number of manufacturers will allow you to test gear, but some won’t.  Also, don’t overlook the stars of yesteryear.