I love them if my dh is with me. I scan he bags and it takes about 1/2 the time to get out of the store. This is at Stop and Shop and we have never had a problem.

The self check outs at Price Chopper are not the same and I never use them there. They have no belts there and the bagging area that they do have fills up to quickly.

You also have to remember that the checkout counter is really a giant scale. You can not remove any groceries to put into your cart unless the bagging area is full and the cash register tells you to clear the bagging area.
And as far as produce you must make sure you have a sticker with the code number on it or you will be looking for help.