Jay,
A reader has to interpret what any reviewer says, for a few reasons. Aside from the commercial bias, the review is only as good as his ears, experience and understanding of music. Who says a reviewer is any more qualified than any listener? In your case, you have good ears, because you accurately and objectively describe what you hear. However, at times I disagree with your interpretations of what you hear.
For example, although I have never heard the Dag S250 or the Momentum 400 mono amps, you described the S250 as more euphonic than the Momentum. As a more dedicated circuit, I would expect the Momentum to be more accurate, and would probably agree with your objective assessment if I heard both Dag's. In my experience, when a product is more accurate and detailed than another, it is cooler in tonality and has thinner images with more focus. I learned this over the years with many products I owned. So that reviewer said, "the Dag had more color, bigger images than with the Rossini solo, a soundstage larger in all directions and set farther back, and the strongest bass." Now, I'll interpret what he said. Bigger images (as opposed to smaller more focuses images), a soundstage set further back, and stronger bass, are all caused by rolloff of HF with more prominent bass, and result in less fine detail. He is entitled to like that, and it is better for him, but anyone who priorities detail and accuracy would say it is not better, but actually worse. Next, he said that the Benchmark LA4 "proved the least colorful and engaging of the lot, with recessed highs and a rather flat presentation." I haven't heard the LA4, but the AHB2 I heard at home for a month showed those characteristics except it had extended HF, not recessed HF. He may have a hearing problem. But it is true that accuracy is associated with less color and a relatively flat presentation. For those people who are familiar with live unamplified music, I have said that COLOR is in the live music itself, and should not have overlay of COLORATION from electronics. Also, the "relatively flat" presentation is characteristic of something with more HF detail and lack of artificial inflation and bloating of images and depth.
The most authoritative views on the Benchmark LA4 are from yyzsantabarbara, who owns it and also values accuracy and lack of coloration.
Lastly, money is the least important criterion of judging any audio electronics. In the detail/accuracy camp, there are the Boulder, Mephisto, Benchmark, my Bryston 2.5B SST2 and Mytek Brooklyn AMP+ products. In the euphonic/pleasant camp, are the ARC, Pass, Rowland, Luxman, etc. In each camp, prices vary greatly. The "levels" are merely money, but not necessarily quality. At each price level, the number of euphonic products greatly exceeds the number of accurate products. BTW, although you don't venture into turntables and cartridges, my experience in this area has also shown only weak correlation of price and sound quality.
A reader has to interpret what any reviewer says, for a few reasons. Aside from the commercial bias, the review is only as good as his ears, experience and understanding of music. Who says a reviewer is any more qualified than any listener? In your case, you have good ears, because you accurately and objectively describe what you hear. However, at times I disagree with your interpretations of what you hear.
For example, although I have never heard the Dag S250 or the Momentum 400 mono amps, you described the S250 as more euphonic than the Momentum. As a more dedicated circuit, I would expect the Momentum to be more accurate, and would probably agree with your objective assessment if I heard both Dag's. In my experience, when a product is more accurate and detailed than another, it is cooler in tonality and has thinner images with more focus. I learned this over the years with many products I owned. So that reviewer said, "the Dag had more color, bigger images than with the Rossini solo, a soundstage larger in all directions and set farther back, and the strongest bass." Now, I'll interpret what he said. Bigger images (as opposed to smaller more focuses images), a soundstage set further back, and stronger bass, are all caused by rolloff of HF with more prominent bass, and result in less fine detail. He is entitled to like that, and it is better for him, but anyone who priorities detail and accuracy would say it is not better, but actually worse. Next, he said that the Benchmark LA4 "proved the least colorful and engaging of the lot, with recessed highs and a rather flat presentation." I haven't heard the LA4, but the AHB2 I heard at home for a month showed those characteristics except it had extended HF, not recessed HF. He may have a hearing problem. But it is true that accuracy is associated with less color and a relatively flat presentation. For those people who are familiar with live unamplified music, I have said that COLOR is in the live music itself, and should not have overlay of COLORATION from electronics. Also, the "relatively flat" presentation is characteristic of something with more HF detail and lack of artificial inflation and bloating of images and depth.
The most authoritative views on the Benchmark LA4 are from yyzsantabarbara, who owns it and also values accuracy and lack of coloration.
Lastly, money is the least important criterion of judging any audio electronics. In the detail/accuracy camp, there are the Boulder, Mephisto, Benchmark, my Bryston 2.5B SST2 and Mytek Brooklyn AMP+ products. In the euphonic/pleasant camp, are the ARC, Pass, Rowland, Luxman, etc. In each camp, prices vary greatly. The "levels" are merely money, but not necessarily quality. At each price level, the number of euphonic products greatly exceeds the number of accurate products. BTW, although you don't venture into turntables and cartridges, my experience in this area has also shown only weak correlation of price and sound quality.