I've used 80/20% but prefer 90/10% for sticks if I have not cut/trimmed my own to grind fresh. That being said, I think the Sam's Club 80/20 is better than the Kroger 80/20 and if I plan ahead will usually pick up 10 pounds or so of meat from Sam's.
I have bought the 73/27% just to see how it worked for other stuff, but there is a lot of fat that rendered out when I browned it. I think it was probably more like 60-65% instead of 73%, but that's just my take. The wife will buy it on markdown, but I'm not a fan of the 73/27% at all. To me you have to factor in the extra weight you are loosing as rendered fat and then compare the "meat" price apples to apples so in the end it's not a good buy (not withstanding how it actually performs). Like I said, I'm not a fan of it for any purpose.