The last time I bought tires at Discount Tires, service was good. But we have a similar tire store, Les Schwab, here in WA whose service is also good. They will patch a tire bought from them for the lifetime of the tire; doesn't matter if its changed ownership.
As for Costco, the only automotive product I've bought from there is car batteries. They were the cheapest and all of them seem to last 5-6 years. As for the shopping experience, its not like a grocery store or department store. Its a warehouse and checkout lines are long due to the amount everyone is buying. Costco was originally intended for business owners. Everyone buys in bulk.
But I would confirm the meat selection is good and the rotisserie whole chicken is only $5; better than grocery stores. Selection is limited if you're used to grocery stores but everything is in bulk. I shop there once a month to get basic food stuff and augment it with grocery store items (stuff I don't use that much like condiments, spices, etc.) If your Costco has a deli, then it would be worth purchasing a membership. $1.50 for a large hotdog or polish dog with unlimited soda refills can't be beat. A large slice of pizza is $2.
Their gas prices are pretty low. Originally, they were using no additives in their gas and people were having problems. Since, they have changed to using Shell w/additives (BIL worked for Shell).
If you want to check it out, find a friend who is a member. They can take up to two guests into the store.