I can only speak for North Texas, where the meats are outstanding. I also agree that Kirkland branded items are generally very good. Their dog foods are very highly rated -- it's all psycho-poodle eats.
The dried herbs and spices at my COSTCO are also excellent. They have some good cheeses, too -- perfect for cold smoking.
But, I mainly have a membership for the fresh meats, and the seasonal seafood offerings. I buy in bulk, and vacuum seal smaller portions for freezing.
I also get things like bulk towels for the kitchen there, but I get them in the automotive area. They work great, and cost less.
Be careful. It is easy to overspend in COSTCO. You can get sucked into "bulk mania." Not every bulk buy is a good buy. Many aren't. You really have to do the math, and decide whether the bulk deal beats what you can get at the supermarket. Sometimes it does, and sometimes it doesn't.