Depends on the Vehicle.
For cars that'll be driven, uhm..."seriously" I generally prefer cloth, ditto for something I'll be in for many hours at a time. For all-weather dog-haulers and pampered toys (now there's a divergent pairing!) I prefer leather.
Sorta wish the S8 had cloth seating surfaces with lots of leather elsewhere, if I were ordering up an exotic that's how I'd spec it.