Huge difference, and I have owned about 15 standards. My R. Taylor puts them all to shame. I think the biggest benefits are provided by the ASymetrical bracing, the solid lining, and very light build. Back when they still made them they had a body with no top or back, just sides with lining. The body with no top or sides was as solid as a completed guitar. With kerfed linings such an example is very flexible.
Tonally the dynamics are so much greater than a standard Taylor. The ability to draw an individual note from silence to maximum volume, the same for a chord, etc. Very similar to the boutique guitars like Huss and Dalton, Santa Cruz, and Collings that I have owned or sampled.
FWIW I dumped the most amazing guitar I ever owned (a custom Huss and Dalton) for a R. Taylor. The R. Taylor is just that good. My previous favorite Taylor I had was a BTO GS with Adi over Cocobolo. It was a stunning instrument both acoustically and tonally, but not in the same ball park as the R. Taylor I have now which is Alpine Spruce over Rosewood.