The short answer is, if you can get a case of "high choice" briskets, I would go for it. Better would be if you could sort through a couple of cases and build your own case. My Sam's Club lets me do this with Prime briskets because I'm looking for other characteristics. Here is the rest of the answer....
Well, when marketing beef in different programs there are sub-grades so to speak that use marbling to separate USDA Choice into three sub-grades, and USDA Prime into two sub-grades. Since not every producer goes the extra mile and participate in separating the sub-grades, it's up to the consumer to compare in the meat case. Below are some USDA Prime ribeye steaks I bought already packaged, straight from the meat case for a small contest, and while selecting I had about 6 or 8 packages to choose from. The marbling in the cap muscle on these steaks was way heavier than all the others, so it was easy for me to call these "moderately abundant". Now it can be argued that grading takes place in the loin, and not an individual brisket.... but if a steer is graded high choice it would make sense that the brisket could fall into the same sub-grade.