On the east coast, Stop & Shop has the best self-checkout experience I've seen. You get a bar code scanner when you enter the store and scan and bag as you walk

On the east coast, Stop & Shop has the best self-checkout experience I've seen. You get a bar code scanner when you enter the store and scan and bag as you walk around. At checkout, you scan the reader, keep everything you already bagged in the cart, and pay. Checkout takes all of 30 seconds. Bonus: you immediately know what each item costs from the display on the scanner.