As someone who presently has a pair of Nilai mono block kits enroute, I would appreciate knowing why I should care there are perhaps comparable finished amps available in the same price range. Assembling the kits sounds like fun, and shouldn't take long. Is there something about their design as kits that will diminish the finished product, in terms of performance or reliability?
No, no reason for you to care at all. But that's because of your particular perspective, approach to amps, and use-case. Many folks, including many members here, view it conversely: why should they pursue a DIY kit if they can get a pre-built unit with a professionally manufactured case, and often a warranty, for the same price?
Neither approach or perspective is wrong; they're just different, and both totally valid.
I'm new to this forum: does value even properly come into play for product reviews? I don't see how it can. After all, the greatest value in amplifiers is found in the cheapest ones. They take you from silence to music, at the least cost. And probably satisfy the needs of a majority of music lovers (with their smart phones and earbuds). At the other end of the spectrum are folks who spend $1,000/foot for speaker cable because they are not limited by price and are easily persuaded.
Personally, for a review I just want to know how the device measures compared to other products, and what effect those differences might have on how I hear music played through them. I can draw my own (nonlinear) efficiency curves.
Welcome to the forum!
You raise a very interesting point, and your point plays into a lot of the discussion here.
The short response to your question is, of course you are correct: the cheapest amplifier that reproduces signals transparently - that is, with frequency response nonlinearities, noise levels, and distortion levels that are below the ability of humans to hear - is by definition the best value.
Of course, in reality it gets more complicated, because there are other questions that are variable based on individual situations and preferences and are sometimes difficult to quantify precisely, but are in my view still within the overall realm of objective qualities of one sort or another:
1. Build quality/likely longevity of the product;
2. Location company and of available vendors - the more inexpensive the product itself, the more the price comparison can change if one item is available domestically with free shipping while another is only available internationally with expensive shipping; and location of manufacturer can also have a major impact on how practical it is to be able to actually take advantage of the warranty if something goes wrong with the amp; and
3. Watts/power/current capacity - do you get an amp with 4x the power for 2x the price of another, otherwise comparable amp? For folks listening in mid-field with highly efficient speakers, the answer is probably No. For folks listening far-field with less-efficient speakers, the answer might be Yes.
Finally, there's the more subjective issue of how a product makes us feel. The science/measurements/engineering ethos of this forum is still an ethos - it still speaks of values that folks bring to their evaluation of products. So having extra power reserves, first-rate build quality, "extra padding" in the performance specs beyond the threshold of audible transparency, and so on - these are things that many folks here like to see in products they consider buying.
Periodically some folks will comment here in threads accusing all of ASR of being a sham or hypocritical because "everyone here chases specs" even when better specs don't make an audible difference, and therefore we are allegedly no different from people who seek out cable lifters, high-end interconnects, and other audiophile "tweaks" even when they don't make an audible difference. The claim is that all this stuff is irrelevant and just makes us feel better, and so therefore measurements are the same thing as snake oil. It's not true of course, but like many bad arguments that refuse to die, it's just close enough to the truth to be misleading.