I go to one or the other now and again, and come home thinking 'blimey, all that food for so little money' but there is always at least one item which is disgusting (this time it was the cider - it tasted like fizzy apple juice with several teaspoons of sugar added). So, if you factor out the horrible stuff, it really isn't that much of a bargain, IMO.
I haven't got time to shop there for what IS good, and then go somewhere else for all the other stuff, and I can never get everything I need from them.
I know they're amazingly popular, but can't see why.