The thing to remember about tools (and most things) is that the performance curve is not linear. The difference between a 4 and a 5, is different than the difference between a 9 and a 10. It's like the earthquake richter scale for earthquakes, where each level is 10X the amount of shaking. At the lowest levels of tools, $20 can make a big difference in quality. When you're paying $250+ for a socket set, the differences are smaller, and you pay more for the diminishing returns. Where does cost outweigh gains? That's up to the consumer.
If generally serviceable Pittsburgh pro sockets, are deemed to be a 5, call gearwrench 6.5-ish. Mac/proto would be 9s then. FWIW I purchased a set of pittsburgh pro deep sockets (the multi-colored ones) and am waiting on their replacement after 5-ish years of rust belt service. They're used daily to make my living, 12/13/14 are getting rather worn. I got my $12.99 worth. Williams USA will be replacing them, williams is another 9 contender, IMO.