Hi Hieukm,
As Mike pointed out above it is indeed interesting to discuss the added value of reviews.
We have submitted 2 Extreme samples for review, 1 with Marja & Henk of 6moons and 1 with Matej Isak of Mono & Stereo. We have personally delivered both review samples to add context to the design priorities, aid in setting it up and provide general background information about our company. Now there is some risk involved with doing so as you can never be sure the reviewer is going to like your product, yet as these are experienced writers, their reviews can provide people with some insights and "what to expect" when buying a product. Of course there is a commercial aspect to this. When a reviewer or a group of reviewers launch a website, usually just as an hobby initially, they start out reviewing products for free to generate content and attract people to their website. When this venture turns out to be successful, time expenditure, general website hosting costs, travelling to shows around the world start to amount to significant costs. It can become so time consuming the reviewers are quitting their jobs to devote all their time on their web magazine. Obviously they cannot live of nothing, at which point they start to include advertising services in the form of banners on their websites. The most popular sites have even converted to not accepting samples for review if you do not buy a banner on their website, even if it's just for 1 month, it's a matter of principle, and at this stage they need to cover their costs of running their websites. A clear explanation as to why was published by 6moons here :
https://6moons.com/audioreviews2/why/why.html
Now I can understand how things may start to look shady at this point in time, you may develop the notion that reviews can be bought, now that may very well be possible somewhere, you can buy University degrees in shady parts of the Internet, why not reviews. However ask yourself this question: Why would people, having invested years of their lives into building their magazine, it is literally their life's work, risk all of that? It is bound to come out at some point in time destroying all credibility and everything you have worked for so hard to build. People like Matej and Srajan have nothing to gain, but everything to lose from walking that path. I have personally met them, these are passionate people who take pride in what they do.
Addressing the awards under discussion:
The Pink Faun 2.16X received an "upper echelon class" award.
The Totaldac D1 driver received an "highly recommended product" award.
The Extreme review is pending.
The "Best of 2019" awards are not tied to these classes, but awarded to products released and/or submitted for review in 2019 which stand out in one way or another.
If we take the Totaldac D1 driver as an example, I think it's a remarkable product, I have personally bought a pair which has replaced my 7 times more expensive Audionet Stern preamplifier (although it's really 3.5 times as I bought 2), so in my opinion it definitely deserves an award. It did not receive an "editors choice" nor an "upper echelon class award", it did however receive a "highly recommended product" award, and it did receive a "Best of 2019" award. I am not aware what the criteria are exactly for these awards, my guess would be the Totaldac D1 driver is not a vital part for system operation. Yet it can dramatically improve digital playback performance, which may be why it received the "highly recommended product" award, and being somewhat "novel" maybe the "Best of 2019" award, but I'm just guessing here. I am also unaware of what motivates the Extreme "Best of 2019" award, it came without an explanation, but it is obviously something different to the usual with a few unique features you won't find in other products, which may entitle it to receive this award, but again, I'm just guessing.
As for reviewers acquiring review samples, it is indeed an honour, and it's no big secret something like an industry accommodation arrangement does exist where people in the industry can acquire products at reduced rates. That probably applies to all industries.