AutoZone seems to be all over the place, which is nice if you have one of their batteries and need to replace it under warranty.
The store employees are not always that knowledgeable about vehicle repairs and very few are ASE certified for parts or anything else. That said, if you shop regularly and get to know the staff, there are some really good ones.
At AutoZone on Palm & Base Line in Highland, the tall, red bearded parts guy Grayson is really good, and I'd give him 6*'s. He has ASE and it shows. He knows parts and cars and has steered me right on my repair work. One time I brought in a part to match up to a new one, and he looked it up on the computer. The part in stock did not match. I was perplexed. He looked at my vehicle and immediately determined the engine had been swapped in from a newer Jeep... must have been done by the prior owner. Anyway, he recognized the engine and keyed the different year into the computer and sure enough, my part matched! This sure answered a lot of questions I had on getting things like plugs to match up... I had assumed then prior owner used the wrong one, but it turns out they were right for the engine.