Five-star
(Other definitions for topnotch that I've seen before include "Superb" , "First rate" , "Informally first-rate, super" , "First-rate, A-one" , "First-rate, A1" .)
(Other definitions for exceptional that I've seen before include "Very unusual" , "Unusually good" , "Outstanding; not typical" , "Extraordinary!" , "Out of the ordinary" .)