I have to somewhat agree. I've used countless brands over the last 25yrs. I'm currently using 3 different brands (Mcintosh, Alpine, Kicker). I've never really heard that big of a difference. A difference many claim to hear as night and day which I just think it's other factors and not amps. Now I think there is certain instances when an amps performance changes with age or internal capacitors loose their efficiency or change rating and this effects the sound. I'm talking amps that meet the manufacturers original specifications. But with all things perfect from amp design to amp design, at least in my experience, there has been little to no differences especially at comfortable listening levels. Then again I've never used junk and have always used a careful selection in my equipment. I used the 35 series Alpines from 89 to 94, regarded as some of the best Alpines (even amps) ever made for SQ. I switched them out for the Mcintosh in the same system same power replacements. Only noticed a difference at extremely high volumes. Mcintosh kept it's composure better but I attribute it to them being more under rated than the Alpines. Otherwise, audibly speaking, no difference at least there. I want to make that distinction but I'm not going to try to compare one amp to another in different systems, just not practical or accurate. I only give credence to those that have switched out amps from the same system in this fashion. Most of it is all BS!!

On a side note, my Mcintosh amps are 18-19yrs old and playing like a champ. My alpines croaked at about the 10yr mark. Every Alpine amp I've ever had lasts about 10yrs then I start having problems. I moved them over to other cars and was actually easier on them. So that's something to be said about running high end gear, or at least McIntosh. My actual Mcintosh rep told me they would easily last 30 plus years and told me to send them in at the 30yr mark to have them evaluated. If they do not meet the original specifications at the 30yrs mark they will fix it till they do. Who else does this?