I'm a professional at dealing with Mario now after many annoying super angering matches. (Cape pisses me off so much because it's so easy to hit Marth with it). The way I deal with Mario mostly is playing the waiting game. Let them make the first move. When I'm playing with fireball spammers, I generally swat them away with a neutral attack, F-tilt or U-tilt depending on where the Mario opponent is trying to come in. F-tilt if theyr'e approaching directly and U-tilt if they're trying to approach from above really. If you time it right Marth's sword dwill go right through the fireball and hit Mario's b**ch a**. To try to counter the cape, I usually mix up my recovery, either delaying it for quite a bit, or immediately recovering to the stage, I try to keep it unpredictable. That cape is the most infuriating thing to me. There are a few videos on my youtube channel of me playing CPU Marios which I used to have just as much trouble with as human Mario opponents. Most Mario's use that frickin stupidly overly long lasting sliding dash attack a lot.. I usually counter that with a short hop N-air or F-air. Ummm... other than that I can't think of anything else. If you get a good hit combo the crap out of him and knock him off stage. I haven't gotten the timing down on spiking him out of his Up-B yet because Mario's Uppercut has way too much priority/frame advantage or whatever the term for it is... I pretty much hate Mario with a passion lol. I think too many of his attacks are overly ridiculous.