Sounds like it was essentially a comedy of errors that allowed this to creep through... if any one of five things hadn't happened amir wouldn't have gotten an amp with this issue to test. Either there wouldn't have been a problem in the first place or it would have been caught early.
*sigh*
I wouldn't take it too hard. The takeaway I'm getting here is that it's a non-issue if you have Hypex modules. The level of distortion introduced via the steel is not significantly higher than the "normal" baseline distortion inherent to NC502MP modules. This is why it went undetected before and Amir gave the Buckeye Hypex amp his recomendation; it performed at the expected level despite the steel tabs. Even with the "fix" applied, the NC502MP module would remain a bottleneck. The modules themselves are incapable of giving you much more.
Contrast this with the ability of Purifi modules to reach relatively lower distortion levels, where the difference between baseline distortion and steel-induced distortion is greater. Remove the steel tabs and distortion drops more significantly. Being capable of significantly lower distortion, the modules can take advantage of the situation. Whether any of these differences in distortion are audible is entirely another question, one in which I suspect the answer is "probably not." But I'm new around here, so what do I know?
By not recommending the Buckeye Purifi at this time, and I suspect this will change upon retesting, Amir failed it for performing below spec (so to speak). It would be interesting to see which amps remain recommended that are
more expensive and perform
worse. I am guessing a few, which is why I disagree with Amir's current blanket non-recommendation on the Buckeye Purifi, but that is a topic for another day.
Personally, I went with Purifi because it runs cooler and thus will hopefully last longer, not because I think it's going to sound better. I still want "the fix" applied since technically I am paying for its better performance capabilities. From this point of view, I understand the reasoning behind the negative review, but I would also advocate an approach of keeping things in perspective.