You know that thing Hax started doing against Marth's where he jumps back from the ledge then re-grabs it to avoid Marth's Up-B. How effective is it actually and should we all jump on this train? also what other characters can use it against marth?
I don't think I answered this question(s) properly. It's most effective when you know that they have to go for the ledge (and can't land on stage) because you know when they are forced to Up-B, so you can time the backwards jump (if you prefer this to complete invincibility).
I guess most characters can do it. The character that comes to mind is Jigglypuff, because of the horizontal air movement. I think that Ganon will struggle to use this because his ledge hop is very short (so short he has a perfect waveland or something). Yoshi, Peach, and Ness can't do this (obviously because of their double jumps). I guess it all comes down to timing it correctly. As Prof. Oak said, there's a time and place for everything