OMG. First, its not an instant 60% against sheik. If sheik can DI out of your combos, y dont u DI out of hers? Now I have a question. Apparently any sheik with good DI can escape marth combo'ing... then how in god's name does mew2king combo KDJ's sheik? Do not say that its because its mew2king. I say this not because mew2king isnt an amazing player, but because mew2king is a pro at combo'ing while KDJ is pro at DI. They are both "pro" at everything. So chacnes are, if you are playing some1 at your level you should be able to find a way to combo them.
I play my normal style against sheik and I do fine. Also, if something is your worst match-up, it is not a counter. It could be a counter pick, but not a counter. Falco doesnt counter fox, most people believe he has a slight advantage. Falco doesnt counter sheik, he has an advantage. Just watch drephen vs (insert falco here). Etc. etc. etc. A counter is sheik vs bowser, a counter is marth vs mew2. Not sheik vs marth. Out of any tilt sheik does, with correct DI you can usually get away. Out of down throw, you can DI the forward tilt away so that you can get a fair in b4 sheik can follow up. If she starts CC'ing your double fairs(though i wasnt referring to the sheik match-up, i was referring to the guy who did it against a DK player), then just do a u-air and she will hit the ground probably not teching. Do a tap "a" reset and sheik cant do **** about it. The only main advantages sheik has in that match-up are edgeguarding/recovering, and a slight combo'ing advantage. And about if they dont CC the fair then they just DI the tipper... how many sheik players do you know that can consistently survive marth's tippers at 80% w/o a sweat. I can, but there are not many people that can do it and not get edgeguarded easily.
If a grab = 60 instant damage, then how do marth players win matchs after getting grabbed? If you DI correctly you wont get 60 damage. I would say the match-up as a ratio is about 5:4 if you are using the ratio that phanna used in his chart. Idk what he put, but thats my opinion about it. Also @ BP, I realize that fox has an advantage over fox imo, considering I just said that last post lol. To be exact I think I said "Marth is overrated against fox, but underrated against falco". Something along those lines =)
Peace