Never heard of BJ's until I received a free 60 day membership in the mail. After visiting this store, I know realize why they send FREE memberships. I found it extremely off-putting to be greeted by the smell of old food at the entrance. It has a gloomy atmosphere and is relatively small.
I was unable to justify spending $50 or $100 for their membership. Especially, since I didn't see any significant savings on the items that I would be interested in purchasing (paper & cleaning products). I do think it is cool that they accept coupons and all forms of payment.
Ultimately, BJ's is too grimy, smelly and disheveled looking for me. It is definitely Costco's distant, twice removed cousin.