It's really a different approach that will yield different outcomes and experiences. Super Cruise works on "pre-mapped divided highways". That suggests it's more like hard coding most of the environment and working with HD-maps. While I don't know what Tesla Autopilot does, Tesla FSD is designed to drive with interpolation of the current input. It's a much harder problem for Tesla to solve but the results mean that it can deal with changes and unusual situations without something like massive case statements pre coding those exceptions.