I could write a novel. I'll keep it brief:
1. Walmart provides as much data as possible to it's suppliers, and expects the suppliers to use this data to then advise Walmart on projected sales and inventory in a collaborative manner. Target, on the other hand, has a data feed for it's suppliers, which is VASTLY inferior, unreliable, and the data isn't nearly as complete. A few years ago, they switched this feed from one system to another, and didn't think it was a big deal that the new system barely worked. This made the suppliers/CPG companies I advised scramble and have extreme difficulty in planning. The buyer teams at Target didn't care, and still expected the suppliers to do the same analysis.
2. Walmart has a religion of keeping items in stock and on the shelves. It's not easy to achieve, and they drop the ball at many stores on this, but it's CLEARLY not a priority at Target. They just don't have logistics as a core focus there, and it shows. My wife's experience of expecting a core item that was on the shelf last week at Target to be out of stock is typical.
3. Hearing trucking companies describe what it's like to ship goods to Target vs. WM is sad. Truckers charge extra for Target because they frequently find themselves waiting hours, sometimes days, at Target distribution centers to get their cargo offloaded. This NEVER happens at Walmart DCs. When trucking companies negotiate contracts with Target, this is something they have to "bake in". It's horrible when you hear stories from mom and pop truckers who get suckered into doing business with Target.
4. Target coporate vs. Walmart corporate: Walmart corporate has a shocking number of very high ranking executives (often in their 30s) who never went to college and worked their way up from working in stores. Bentonville, Arkansas is filled with these folks. They have a real "gut level" understanding of the stores/DCs and this is probably the only reason Walmart hasn't collapsed into gross mismanagement. Their worst executives have always been external hires. At Target, it's rare to see people who worked their way up internally in high-ranking roles. Much more typical corporate environment there.
Well, wrote a novel anyway. But yeah, that sums it up.