I purchased once fired brass with excellent results on GB several years ago, but that seller doesn't seem to be active anymore. As with any product, results could vary from seller-to-seller.
https://www.precisionbrassops.com Theses guys for .223 All of their brass is once fired Winchester that has been completely prepped including roll sized, trimmed, chamfered, and deburred
Sorry, I tried to find the last supplier I bought .44 mag brass from, but the GB history only goes back for 90 days. I usually browse the listings and try to find the best per case price consistent with the seller's description of the quality. BTW, the new GB format makes browsing and comparison much slower than it used to be. I've always been satisfied with my purchase. Wish I could be more help.