I worked at Wal-Mart for two years while going back to school. Several family members of mine have worked there, including one who is a career employee.
I can type reams of information about the experience and what I think of the company and whether you should shop there, but I'll try to hit the highlights:
1. Wal-Mart is unquestionably not perfect. However the arguments made against it are more often than not skewed or flat out ridiculous. There is some valid criticism of Wal-Mart naturally, no one who is this big and rich and powerful in their industry is going to have absolutely nothing to answer for.
2. Experiences vary widely. Wal-Mart did not particularly value me as an employee and working there wasn't enjoyable, but I can't say they were unfair. I felt I had reasonable opportunities and at the time I honestly felt like it was my best option personally. I feel I could have been better treated but I also feel I was reasonably treated. That's just me personally.
3. I feel Wal-Mart is at worst morally ambiguous. They aren't the problem they're the symptom. Globalization, the efficiency demanded by the information age economy, consumerism, all of these terrible things Wal-Mart gets blamed for it did not create. While the company does have agency in the portions of those phenomena it is responsible for, it did not create these problems as is often alleged (see #1).
However I also saw a lot of things at Wal-Mart that are good or at least well intended. Safety protocols for example are very tight and go beyond the standards they're based on. Outside of two unfortunate exceptions dealing with one incompetent person, management did not let customers abuse employees. Wal-Mart does contribute to employee's retirement. Believe it or not most of their employees do have health insurance (that used to not be true but they set out to remedy this and succeeded). The company is one of the least wasteful places I've ever seen, if it's not necessary it's gone. They police their own trash and waste admirably and even clean up the area around their stores (at least the two in my market did). Wal-Mart provides jobs and goods and services to people who are disadvantaged in various ways.
I can't morally fault anyone for not forgiving Wal-Mart's shortcomings nor can I fault anyone who praises the company for its strengths. These are just competing value systems at play and I'm not entitled to say whose values are better.
If I had to say one good thing about them particular to my experiences, it's that Wal-Mart gave me a badly needed income at a low point in my life where I had all sorts of problems, and it afforded me a chance to pull myself up by my bootstraps. I don't work there any more because I moved on to something better, but I wouldn't have moved on to something better without going through Wal-Mart.
I started at 8.90 an hour. I ended employment there with wages topping $11 an hour, plus I had health insurance. Again this was within 2 years.
And where the store was at, these were competitive wages in that locality. It wasn't an area with a lot of high paying jobs at the time.
I probably pocketed about $900 from additional perks like bonuses, stock purchasing, etc. It's not a grand sum but I really needed it at the time.
It's not the worst job I ever had. It wasn't a good job. It was just work.
The worst thing I personally saw about the company is that the people at the very top are rich, well educated executives who don't know what it's like to stand on a concrete floor and push items across a register all day. They are people who only understand metrics they can see.
They don't understand that they have some employees who are career workers who provide far more value to the enterprise than others. They don't realize piling more work on fewer people only exacerbates the problem. I really doubt they understand how much your feet hurt after walking on the concrete all day.
They make decisions driven solely by metrics they define themselves, and then when the situation goes badly, they just change the metrics. The people who have to carry it out are never considered in the process.
But I have worked at other places that were just as cruel and soulless. Once an organization gets to a certain size, no one in the organization can feel completely loyal to all its members.
Best experience working there? It's the only place I've ever worked where both customers and employees told me, unsolicited, thank God for this company. The customers especially make you feel like you're doing something that matters sometimes. Their stories should all be collected and put into a book.
Worst experience? Well besides the general soul crushing tedium and the fact you have very little say or control over how things are done, the worst part is seeing people who have worked there for a long time getting pay cuts and other things like that which aren't fair.
Strangest experience? Hard to say. Truthfully the rudeness of the customers is just something you harden to over time though I do have some war stories of some really quirky people. The People of Walmart site still makes me laugh because for good or ill the Wal-Marts just seem to attract the weirdoes. It's neither a good nor a bad thing it just is.
When I worked there I never took it personally if someone didn't like Wal-Mart. So shop there or don't, I can't define your values for you, but for whatever it's worth I've been in the belly of the beast and seen some things I thought weren't right and I still shop there. For whatever it's worth, even the people who work there tend not to buy everything there. Meat and produce have never been particularly strong products.
Personally I still go there, though I use a local chain store for most of my grocery buying, but if I need some antifreeze or something, Wal-Mart's fine.