I agree on the point about kirkland signatures goal.
Let's assume for fun that it is not a goal, but an actual claim the balls were "equivalent or better than leading national brands". Every single term has to be defined, and likely in court, since those are not legal terms. Leading national brands is plural so, top 3, top 5, top 50%? Then, in golf balls each brand has many different balls. So, which products are we comparing from each brand. Then, what parameters are golf balls measured against each other. Once we have that what does equivalent or better mean. Equivalent in plain English does not usually mean exactly equal, and there is such a thing as measurement error. So, equivalent could mean within 5% of the leading brands in whatever parameters are measured.