Never used saddle soap on my car's interior (and my girl has horses and is an equestrian jumper - so we have it around the house). Leatherique
Rejuvenator and Prestine clean are where it's at for what I consider to be the best leather care products out there. It truly is amazing. Rejuvenator takes time to do the process correctly, but it totally refreshes the leather and makes it nice and supple. Prestine clean for in between cleanings.