Pros
You'll learn how management SHOULD NOT work. You'll learn not to trust your boss. You'll learn to avoid customer questions because you can't tell them the truth . You'll learn to take an insult and keep working. You'll learn to keep your head down and be silent while others are being chastised. You'll learn that a "productive" work environment includes silence and barely acknowledging your coworkers.
Cons
Seriously, though, it was a miserable job. I liked my coworkers, although I barely got to know them because if you exchanged more than a couple of sentences that weren't work related, one of the bosses would suddenly appear to ask if you needed anything. That was the only time they did that. A few long-term employees try to make excuses for the owners and say that they mean well or that they're trying to get better. But it's not enough to make up for the way they treat people. They do serve cake on birthdays. And I guess that's a benefit. And they talk about a wonderful future and how much money we'll all have some day. And that sounds nice. Meanwhile, you're broke, overworked, underappreciated, and miserable while you go about your work and try to avoid the owner's direct attention.