Our two "s" types (and the one LC9) have all functioned fine with everything I've tried. Each was tested with 124 grain Gold Dot and Federal HST, but mostly they've fired 100, 115 and 124 grain plated (90%) and jacketed (10%) rounds.
Ours have not been picky at all; choose your favorite premium round for business and any decent range fodder for pleasure. +p+ should be avoided; +P is fine but a constant diet of higher pressure ammunition will as is oft stated, accelerate wear. Follow Ruger's guidance on this.