Some of the absolute best briskets I have ever cooked have been graded Select it's technique + temp & time that win the day. When I pick out a packer the last thing I look at is the grade. I look a Price per lb, overall equality in symmetry,weight between 12-15 lb and a tail no thinner than a min of 1". Once I sort the likely candidates I look at the marbling and make the final selection. If it is a select fine, choice that is ok too. Never saw Prime in my life for sale and to be honest I would never spend that kind of money they bring to get one. BBQ at it's bare roots is all about taking the worst cut & turning it into the best cut. Some seem to forget that and compensate by buying a higher quality. Those that Can, Do, those that Can't, Cheat it.
I never met a Cow that I didn't like with a little Salt & Pepper! Certified PORK-A-HOLIC