LOL CRZ is a genius. I would've never realized I do that.
@knuckles213: If I tell you everything, it'll be a world of text.
This is how I fight MK now, maybe you can check that out.
http://youtu.be/UCT45lQ7oRo
facing mk
In general, I roll away if he gets behind me, or through him if I can't read him. For landing you either fast-fall air-dodge tomahawk (preferably buffered + learn how to buffer turn-around tomahawk too), land with nair (maybe space it so shieldgrab/nair from block don't work), or drift away (plus air-dodge maybe); any of these preferably with a downb right before. Land into utilt works too but only after they've given up blocking because of your tomahawks. Players are used to, well, every other char in the game more than vs Fox, so they're likely to act as if your downb (probably Fox's best move, definitely his best defensive move) doesn't exist. The rest kind of takes care of itself but I do need to get better at using usmash.
usmashing mk
Some of the ones I know are walkblock into a dtilt and usmash it, block a dsmash and unblock dash usmash, block a landing aerial and usmash from block, dash usmash if he glides through me after an upb, forced airbreak dash usmash (you force an airbreak if you pummel immediately after grabbing him out of the air, although they may also airbreak if you see them struggle like a *******), delayed usmash vs his block (to hit the startup of upb/roll/shieldgrab), spotdodge his dashgrab to guarantee an usmash (it has big cooldown), face away from him, block his dash attack, usmash from block, if he whiffs sh fair too close to you, dash usmash as he's landing back to the ground, turn around and usmash on super prediction vs his roll, and stuff like that. As I write this I can't believe I forgot that weak nair to usmash and dair to usmash exist. With the dair, you can dash up to him, SH dair him AS YOU RISE, and when you fast-fall, the landing hits will combo from the rising ones (WTF!?), and you get your usmash. This is great because it not only works if the dair initially connects, but if they block, it's likely that the falling hits will shieldpoke. There are tons of ways to usmash him but I have to list them all so I use it wisely or on reads and not like a ******* that gives away 50% (which I have to admit I do freely when lazy during friendlies).
banana footstool infinites
By the way, I learned Marth's banana footstool infinite. His is a triple footstool one that goes back and forth to the same spot. He can end it with tipper dsmash or tipper fsmash, his choice. It's great, LOL. But he can only do it in FD and spots like the very center of Battlefield.
I'm pretty sure that Fox's is the easiest banana infinite in the cast. He has single, double, and triple foot-stool whichever you want, and 2 ways of continuing it (face where you want him to go and hop+footstool, or face away from him, toss banana down which sends him into you). Doing Fox's infinite on Smashville though, is one of the most technical feats in the game. It requires you to maneuver around the moving platform by judging which actions to take. At least he CAN do it, unlike everyone else besides probably DDD (I'm sure he's great at it because he also has a 5 frame hop and fast-falls even quicker).
Sorry for wall of text time but it's nearly 5AM right now, the wall of text time of the day when you haven't slept at all.