The ops managers will make you or break you. In truth, this can be said of ops managers, AGMs and GMs. If they don't have your back, you are done. My ops manager would write people up first and ask questions later and this led to my demise (as an area manager at least). While I agree safety is important, Walmart takes it to extremes. They demand you go around the warehouse looking for "proactives", basically, an excuse to write employees up for various safety violations. If I wanted to spend time doing things like this, I'd become a cop, not an area manager. If you didn't do one at minimum once a week, you had management on your case. If any sort of accident happened, and you presented your associate's case to the board, they'd ask you "what level of discipline would you issue in this situation". This was a loaded question, as you would answer, and present your case, only to find out the ops had his mind made up already and it became a way to attack you for being too lenient (or just to attack you period). You THINK they are actually listening to you, but no. (And I dreaded hearing an associate had an accident - not just because I genuinely cared for my people, but because this meant lots of paperwork, meetings, e-mails,and other interruptions to an already busy day.)
There was lots of paperwork and reports to file every night but at least when I was working with the right group of guys we'd divvy it up among ourselves and pound it all out in about an hour. But then, we'd have to high-tail it out of there lest our ops come down to visit us with a "good idea" that would see us working there until 5 am if we were on second shift and everything was done by 2 am.
Finally, though they ARE good with Reserve time, one time I went on my two-week tour, and when I came back, I notified HR that I was back at work and ready to start up again. No problems, right? Wrong. They didn't pay me for two months afterward, and it took a great deal of work to get the wheels moving on that so I could get paid again as usual. This severely shook the confidence I had in them.
Another problem lies in whoever the GM is. My first one was very laid back - almost too much, but overall was a good guy. The next one was chock full of ambition to move up, and if his ambition meant driving his area managers into the ground? Well, so be it. Suddenly the plate that I had just begun to manage fairly well was overflowing with all sorts of additional duties and things we had to do during the week - even, at one point, a mandatory five day week when I was initially scheduled for four. This led to lots of make-work items and area managers constantly running into each other, but the GM couldn't have cared any less if he tried. He had his ambitions and that was that.
To go back to the headline: if you MUST work for Walmart, do so in a place with a competitive job market, such as a major city or in an area where different employers compete over a limited labor market. If Walmart is practically the only game in town, stay far away. The reason is simple: if they are in the former category, you'll have more leverage, and upper management will know this, and treat you accordingly. If the latter, Walmart management assumes the attitude of "Well, where else are you going to go? We can do whatever we want to you." (Even a period of high turnover - which I have seen happen - does little to alter that overall attitude.)