Just A Thought : Here are a few universal issues to mention with amplifiers; the design , execution of the design and manufacturing process. If the design is properly engineered and is fully executed in the manufacture , the product should produce the expected result. Makes no difference if we are discussing widgets or amplifiers. The greatest difficulity is execution. With lots of compromises made for reduced manufacturing cost, each has a impact on the finished product. For example,when one examines Edison's machines/processes, those machines in exsistence still work and most to his qualifications, and most are over a 100 years old. Its simple and time honored , garbage in garbage out. Superior engineering & design in , superior manufacture in , excellent results out. Hasn't changed since the clovis spear points to today. But what is important is to recognize what is "real" vs what is "hype". And for that only your circumstances and your ears are the ulitmate decider.
The sole point in acknowledging the A-500's had to do with the fact they were such a surprize (for the money) and that perhaps a cash strapped audio-head would see them as a hold-over or a reference, as they decide.