they are all very nice markers and have owned and shot all of the sl markers personally i think the sl66. On the other hand they are all pro level markers that have crucial changes added to them compared to the standard of that gun years marker.
ive heard lots of talk
what is the best sl marker
I think you left out the best and most rare sl model.....the SL91.
Jack Wood's serial #001 SL91, GSL #001 BLACK,20th Anniversary set #8, Vicious CSL,], ICON GEO3, Boston Paintball Reaper GEO3 , 187crew LV1, Boston Paintball Custom Twister LV1, Hurricanes SL8R, Infamous Johnny Cash SL and everything is older like me and no one cares