Kirby is a very interesting character, one I'm periodically playing very much as. His biggest problem is that he has difficulties delivering really clean hits. KOing with him requires lots of small hits and when confronted with characters like Fox or Ganondorf, it's not something I've very good at. With Luigi I can stay at a reasonable distance and move in for the odd air kicks, but Kirby's just not that good in most cases.

That Kirby's long-range attack (up+B landing) is particularly weak doesn't help either. Jigglypuff (B), Luigi (left/right+B) and Captain Falcon (down+B) all can make a reasonable comeback after being knocked out far enough and do some damage doing so.