If Ganondorf is Capt.Falcon's "hard mode", then Lucina is Marth's "easy mode". Unlike her relative, Lucina is more balanced, and the power from her sword remains even throughout it, and not from the tip. She's still just as quick as Marth, and still has the same combo potential as him, so if you're starting to main Marth, then she's a great way to start getting the hang of things.