There's only one way to find out: buy a couple of boxes of four or five different brands and head to the range. For instance, I've found my my best groups with Winchester BRIs (ragged one-hole at 50 yards) but had Remington Copper Solids string vertically more than 9 inches during the same session. Every gun is different, and every brand of slug load is different. You need to find which brand works best in your gun, and then stock up before the season.
BTW, after the BRIs, I had good results from Lightfields and Federal Premiums, but the Brennekes and the Winchester Platimum Partitions were all over the paper.