It never works to generalize as there are plenty of exceptions to every rule.
That said, I'm going to generalize... working for a privately held company generally beats working for one owned by the stock market (or even one funded with angel capital). The latter will do anything and everything to increase profits, including taking away workers' rights (lately, Lowe's, Hobby Lobby, etc. have been spending a lot of money to no longer have to pay/compensate workers who injured themselves on the job) and buying up competitors so they can squeeze the customer for more money for worse service.
Of course, what makes the whole thing so confusing is that properly compensated workers in jobs that require skill are far more productive than their less happy counterparts. Then again, many of the places where people are treated like crap are the kinds of places where they just need a warm body rather than somebody educated/skilled.