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

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.

Pass labs it good, of course, but even beter is Audio Note,Gamut,Esoteric.Pass missed “something in the mid” and not so holographic an the other ones.
The speakers are very inportent . Use the Ilumnia Magister in combination with. That’s pure natural music!!

I am a professional A/V reviewer and have had many systems in my home and currently all three of my systems have Pass electronics. My situation may be different from those who have written in previously because when I evaluate new equipment such as speakers, I need to have a reference point to assess their voicing. The most critical thing, IMHO, is to have the opportunity to see how amplifiers and front end sources work with their speakers. There is little science here in that specs on the bench will not tell you how an amp will sound with your speakers until you actually hook it up. 
For those considering the purchase of a stand-alone amplifier or integrated amplifier, one of the most important criteria is reliability followed by customer care.  I have had several amplifiers leave my system on those grounds alone. 
Since bricks and mortar audio stores are not as prevalent as they were two decades ago, it is worth while for potential customers to contact the manufacturers directly. A good company will tell you what speakers they have used in designing and testing their amplifiers. An even better company or dealer would give you a 30-day trial on a demo unit. 
So using the term "best" is not the right question to pose, as there will be no "best" amplifier for every system. For cakyol, $15K opens up a lot of possibility and, in my experience, the biggest bang for the buck is investing in good separates that can be individually upgraded as the need arises.