I'd need to run through a few cases before I'd be comfortable using them at a competition. My cull rate was about the same as Randy's, so on a per-rack basis that's about $19.50. The flip side of that for me is that the Costco Swift racks run about $35 for a three-pack. If I get two good racks from each pack, that's $17.50 per rack. If I get lucky on the middle rack, that's under $12 a rack for ribs that generally meet my other requirements.
Restaurant Depot ribs have been a nightmare for me (50%+ cull rate when they're 3 or 4 packs; better in 2-packs), with a nice sprinkling of stinky ribs in there for good measure. I'd take Creekstone any day of the week over those. But since I'm lucky enough to be within a 20-minute drive of four Sam's Clubs, three Costcos, and various other places selling decent commodity ribs, the convenience of hand-picking the ribs is probably going to win out for me.