It’s interesting that you mention Costco.Costco coffee, except for most of it's house brand Kirkland Signature, is a regional thing from what I can tell. Near me they carry Mayorga Cubano roast and one called Ruta Maya. The Mayorga is decent. I don't remember how good or bad the Ruta Maya was but I almost always return to the Kirkland Colombian Supremo and Peets Major Dickasons. The Costco brand roasted by Starbucks is pretty good too.
We actually just got a membership there, primarily for the diaper prices.
I actually need to go in there in the next couple of days, and get my card. (Wife went in there and got hers yesterday)
If I remember right, that Major Dickasons is pretty dark roasted. Seems like you gravitate more towards darker roast?