I have 5 pair of genuine Ugg boots and have two pair of Costco shearling boots I bought a couple of years ago. They look and feel exactly like the Ugg boots...the quality is exactly the same.
Granted, shearling boots are not the same as the woven knit of a BD cardigan...but my point is Costco really does a great job of sourcing quality products, especially under their Kirkland brand. Based on that, I'd be interested in looking at these cardigans. If for no other reason that I can try them on in the store.
I own one BD cardigan and have ordered and returned two others because of fit. For me, BD is all over the place in their sizing. So checking out a BD-like cardigan is a no brainer. If the fit and quality are good, I honestly don't care what name is on the label.
Be kind, for everyone you meet is fighting a hard battle.
~ Ian Maclaren