I use jigglypuff, doctor mario, ness, and young link.  I never lose with jigglypuff. The best thing about her is that she is more powerful when she fights more than 1 opponent at a time because of using rest.  Rest against >28% = OHKO most of the time, except against the largest characters.  So, when everyone is in the middle of a big fight, jump in the middle of the fight and rest, killing at LEAST 1, and more often 2 of them.  Also, ROLLOUT For the win!!!!   I like changing the language to Japanese so the game calls her Purin.