i'd say that silkolene is one of a handful of top tier oils,along with maxima and motul as companies that have the better base stocks and use high percentage of esters in their top oils.(i would add RL here if they offered more varied weights for me to consider them MC specialist.)
there silkolene pro 4 plus is particularly impressive.(and probably offers the higher percentage of esters)
if i were to try and be hyper-critical here,i'd say that my only complaint is that they seem to use Ph and ZN levels similar to many auto oils,they are after all SL rated......and they also take the no-moly road. if i were to take an educated guess,i'd say this is because many new euro bikes come with cats and certain countries in europe test bikes.
most americans just put on slip-ons.
...but it's still awesome oil.
there titan line is also top notch if little known here.