Here's the link to these AmazonBasics batteries on Amazon: https://www.amazon.com/gp/product/B00MH4QM1S/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=B00MH4QM1S&linkCode=as2&tag=beaureviawes-20
Incredibly good bang for your buck
Video side-by-side comparison with what Costco sells.
Both are brand new batteries.

You'll see Amazon has the slight edge in terms of the power you get when it's under load.
Also considering that Amazon is much cheaper.
★
☆
Original review from Beau Chevassus, Knok Studio (Media for non-profits), http://www.knok.org (Seattle nonprofit) Knok.org
From Beau Chevassus: http://smile.amazon.com/gp/profile/A1IJUCICSBF7LA