I like BJs, but don't get a membership every year. We also have Sam's Club, but no Costco. I un-Walmart, so Sam's Club isn't an option for us.
Whether or not it's worth it depends on what you buy, obviously. We probably cover the cost of the membership when we do have it. Sadly, my husband is convinced that our pets need freakishly expensive pet food made only from organic, pasture raised unicorn meat. Before my husband went off the trail in his mind, BJs sells decently priced, reasonably highly rated dog food and we would cover the membership with that alone.
They also have some things at good prices that I can't find elsewhere. Their bulk yeast is amazing. If I buy a package, I can store in a glass jar and use it for baking for a couple of years and it is awesome. I like their house brands of a lot of things. But some stuff cheaper on sale in regular supermarkets or Aldi.