Sam's Club or Costco?

Chris and I are finally going to get a membership to one of these. We had one when we first got married and never renewed because we just didn't use it that much.

But with a very hungry toddler and being a CARES Team with Apartment Life, we really do need to buy in bulk!

So weigh in... which one do you use or have used? What do you like about it? What don't you like about it?