beaut, beauty, bee's knees, cat's meow, corker, crackerjack(also crackajack), daisy, dandy, dilly, doozy(or doozie also doozer), dream, honey, hot stuff, humdinger, hummer, jim-dandy, knockout, lulu(slang), nifty, peach, pip, pippin, ripper, ripsnorter, snorter, sockdolager(or sockdologer), standout, sweetheart

marvel, phenomenon, prodigy, sensation, wondercatch, crown jewel, diamond, gem, imperial, jewel, pearl, plum, treasure

something else

bust, disappointment, dud, failure, flop, lemon, letdown, loser, stinker, turkey