what the Lion said,...I was with B'wick before DynoThane,..B'wick balls seem more condition specific, and had to be changed quicker as the lanes change,..I can stay with a D/T longer as the lanes transition,...also the shells seem to keep their prepared surface longer on the D/Ts,...B'wick seemed to track up quicker...Both are great balls,and what works for some don't work for others,..