counterpicks should be based on your opponents style, and where he likes to go. also, if you are uncomfortable somewhere, ban it. its not entirely character dependent, its different from person to person. i personally enjoy neutrals more than other stages, but ill go anywhere else if necessary. try to notice where you opponent likes to go and ban it. also keep in mind things like how big the stage is, where you can get kill moves, etc. many falcons dont like Fountain, yet it has reasonably small sides, ideal for knees near the edge. banning levels you "dont like" isn't as big as an advantage as banning levels your opponent loves. remember that, and learn to like all stages, so your banning can be based around your opponent's weaknesses. i often ban battlefield on everyone because i hate it, and because im comfortable almost everywhere
Fox - fox is pretty versatile anywhere, kills falcon off the top quicker on small stages, yet so does the knee. corneria has a small ceiling without small sides so that could work good on foxes that like the stage.
Falco. lots of people don't like FD because of lasers, but once you get used to getting around them you can be comfortable on it (i am anyway). falco also ***** on rainbow cruise (yayuhz). i hate battlefield, but ill sometimes go there on space animals just in case they also hate the stage, and try to abuse on the platforms.
Marth - i find this match to be even, just be prepared for the consequences of stages. FD is great for falcon, unless you spend time off the edge. its my opinion that marth ***** yoshis story, but knees kill him faster so its a judgement call. i like dreamland because falcon lives longer due to marths lack of kill moves, just dont get gimped off the edge. find your own strats.
Peach - i often ban Mute City on peaches. many peaches go there, and dreamland is also a popular counter pick for peach. its really a judgment call vs peach, whichever level you like the least out of mute/brinstar/dreamland. i enjoy playing on dreamland because peach lives longer than other neutrals, but still dies reasonably quick with knee, and the level isn't ********. ive also grown to tolerate brinstar..... sometimes.
Shiek - shiek outmatches falcon in virtually every category except for amazingly strong kill move (knee). this is a tough one, i usually ban battlefield/yoshis, whatever im in the mood for at the time. notice your shiek-opponents tendancies and find a stage that counters them (vaguest advice ever lol). smaller stages kill shiek quicker, whereas shiek can gay falcon anywhere, remember that.
Samus - ban dreamland. just ban dreamland. do it. do it right now. every time. right now
