I first bought Opsin after reading about it online. Normally I just used what was available and cheap off the rack. So I purchased 15# test at a west coast fishing show and BAMMM! the difference was in the line, easy to stretch easy to tie and perfect for my Sand bass and Calico fishing. Since then all I buy is Opsin but when they"re out I'll buy some Japanese brand but I still will buy Opsin if it's in stock. The Opsin Quad Pack is the best way to buy so as to make sure you always have on hand.