Typically, Americans do not shop for reliability, quality, or any other variable aside from price. So the question you can answer might be "what is the best 6 CFM compressor I can get that will give me a minimum of grief, with long service intervals and a large sump so I only have to change oil once a (insert time here), that has dealer support for parts and service, and has easy to source long lived filters". That is not a question an American would ask, to my eternal sorrow.
An American would ask "what is the best (with no indication as to what they consider best) compressor I can buy for (XX) dollars."
Of course, the second question is completely subjective and totally depends on the asker's value, which is obviously price point.
So an American sees something he feels he can afford, he buys it, and his sorrow comes along later when he has to change filters every 11 fills or he has to change oil every 2 months or whatever.
Someone in the third world values a compressor that can run thousands of hours and he has to remember to order valve service kits at some point. Someone making his living with a liveaboard dive boat values the same thing.