I got my Costco membership and have already shopped twice in a week. I like it so far besides a few things which I will mention below. You guys were right in saying that you cannot leave there without spending at least a $100 (a little exaggeration but not much). But on the other hand, you won't need that product for a while, in most cases.
The employees all have been very friendly. The aisles, for the most part, are big so it makes it easier to maneuver the the humongous shopping carts. You have to get one of these in order to shop at Costco.
Shopping at Costco is not a casual shopping experience. It takes longer to shop, the lines can be long as well.
I like the shopping experience, if you can call it that, better at the local grocery stores or Wal-Mart. Maybe its the clientele, the atmosphere or something else but it feels slightly out of place shopping at Costco. Maybe its because I'm new to the place. The whole check out experience, with the no bags used, is also different.
I think for buying things in bulk, Costco might be OK. For everything else, the local grocery store or Walmart cannot be beaten. Though for healthy frozen items, such as veggie burgers or fish burgers, Costco is great. Their selection of rice, meat, seafood, cheese is also better than Walmart or the local grocery store. So if one wants to eat healthier and eats meat, especially, then Costco would be great.