You know how when a actor leaves a show and some sitcoms hire another actor to play the same part? Well, who in your opion was the best replacement and the worst replacement. some you may think of could be

Becky from Roseanne
Darin frome Bewitched

Mary Anna Mobely replaced Dixie Carter on Diff'ret Strokes as Maggie. i always thought that Mary Ann was better than Dixie.