Marth is a G&W counter IMO. This has been a recirculating topic over the last few days actually, so I'll just repeat some major points that were broken up.
G&W is mad predictable. KNOWING what my opponent is going to do, Marth is able to fully utilize counter in this match, and that's devestating to G&W. From G&W's perspective, I'd spam a lot of Fsmash, since it'll clash with anything Marth throws in the ground, and if you see him jump, you can UpB through him (UpB will trigger counter if thrown, but G&W won't get hit). If Marth tries to counter the Fsmash, just charge it. ****, mindgames for a really early K.O.
EDGEGUARD MARTH. Seriously, if you happen to Fair him while he's offstage, it can be bye-bye stock. Marth really is easily gimpable, if he messes up his DI in the tiniest bit.
Use Chef a little. Don't leave yourself open, but it's a really good zoning tool, that stops Marth's momentum. Throw like 2 piece here and there to slow down the SH appraoch, and maybe make an opening for a Bair/Dtilt
Dtilt is EASY your most reliable move in this match. Use it.
COUNTERPICK ORPHEON! The part with no ledge basically says "****, I'm going to UpB right into his shield and die at 60 when he Usmashes out of shield.
If Marth is going to recover back to the stage, hog the edge with good timing (I'm quite sure a top level player like you has mastered this). The landing lag on Dolphin Slash is stupid. If you're under 100% you MIGHT be able to stand and Fsmash (I'll test and get back to you if I can). You can DEFINITELY Nair him. Also, ideally, you want to hog the edge, and then Nair Marth before he lands after he UpB's past you. This way, when he lands, the dumb glitch will activate and he will STILL have landing lag. Then you can Fsmash. Whasaywha?! Nair to Fsmash? Combos! I haven't tested how effective ledgehog -> Uair is if perfectly timed. Ideally, you'd push Marth up after his UpB, while he's still in vurnerability, and then you can fet a free partially charged Usmash if you read his landing correctly. That should kill stupid early.
Mess with his spacing by WALKING away from Marth. People are used to retaliating from the shield in this game. Marth has some of the best shield pressure in the game. Simply walking around a lot can mess with his spacing, and possibly cause him to overexert himself, making him throw a Fair he can't hit, leaving his nose open to get bitten by a turtle. It's also okay to walk toward Marth, and do nothing, since you'll be able to react. When in doubt, UpB, but try to stay away from Dair. Counter ***** that shiz. Test it out a bit, and see if doesn't really like to counter, but expect it.
Uhh, thinking if there's anything else . . . Utilt is good at close range, it beats out most dodge options and is very quick. Mix that up with Dtilt a lot, you know how to play.
Umm . . . OH! Juggle, Juggle, Juggle! Keep Marth cursing his wish for MK's wings. Uair him till the sun goes down, and if he gets close, Nair or UpB. When in doubt, just throw out random Uairs. Marth jumps a lot, and it's stupid how often you'll probably make him fly up when he's trying to Fair you.
I'm relatively certain you can UpB out of shield to get out of Dancing Blade with your shield still intact, but if it's full, just shield and punish.
If I think of anything else, I'll come back.
Sorry for being a traitor Roy_R, but Hylian is mad cool peoples.
Oh, and Marth has a positive match-up vs. Diddy btw. All the character that have been mentioned in this thread besides Snake and MK are disadvantaged to Marth. If your Falco is solid, perhaps that's a good idea. I personally have a harder time vs. Falco than G&W, since I can rely on Counter and Dolphin Slash, and Fair and Dtilt are so good vs him. These things are still good against Falco, but lazers can just mess with you at times, if the player is really good at reading your attack patterns, Falco can respond appropriately.
. I can never grab him unless we play on FD.
jk
