Yeah, IKEA hasn't been great at answering questions while you are shopping but I actually like the checkout process. They do self-serve well there. IKEA also epitomizes DIY in general.
I'd say my experiences at Apple Retail Stores have generally been positive but have been inconsistent and certainly has room for improvement. I don't like how the checkout location sometimes varies (back, front, handheld) but I admit overall, Apple does it better still than most retailers.