Started using Mac today for 50-ish games... and my past 50 have a winrate of around 90% (With Robin, I was getting 60%-70%), and that's with sticking around against tougher matchups... though, when someone wins, they seem to leave versus LM, I've noticed. He was beyond intuitive (even getting a few Nair gimps took no practice-- not any sleight to Mac, just that he fit like a... um... glove. Not necessarily a boxing glove, but... XD). But yeah, lost a time or two to a fantastic PacMan (he used his Up B to force me into the air quite cleverly-- though he didn't appreciate the Nairs and slip counters that ensued), exactly one loss due to jolt haymaker SD (stage zoomed in, couldn't keep track of the edge, was a reflex to hit a projectile-spamming Link >//<), and a downright hysterical loss from my running into a Dedede's inhale, lol. I think another might've been against a really good Greninja (they used shadow sneak to recover... that takes some serious fearlessness). Though, other than the Dedede, I got to play against each again and ended up taking more wins off of them than anything...
That said, I'm some sort of idiot savant of KO punch reversals, else that'd be more like 80%-- I've hit Falco out of his side B by some freak luck of a reflex. I still miss a third of them or so, granted, but I've only been gimped a handful of times, myself... Ah, but Marth I'm strictly losing to, thinking of it-- lost a best of 3 to one and haven't played any Marths since.