I worked operating loaders and diggers for various small owner operator companies dealing with the bossman and owner directly and it was always hell. Even the nicest boss was always insanely tight and health/safety was nonexistent, you learn pretty quick to bring your own PPE because nothing is provided. Always nervous about something breaking while using it because the boss gets mad even if it's not your fault. Another thing is how your job is never clearly defined, basically if the boss wants you to do it then you have to do it.
Working for a large company doing the same thing I love the power in numbers that being part of a large workforce brings. The HR is an annoying but potentially useful barrier between you and higher up. Much much better equipment for each job and heath/safety practices. My job is very clearly defined and they have someone trained for every different task and they're a lot looser with money as well as paying much better.