As someone who couldn't care less about fighting games, I find the SSBM controller situation fascinating
Apparently some top players to spend thousands of dollars on controller mods to get a good controller and, before there were controller mods, maybe even more to find a good copy of a controller?
And there are all-digital controllers that fix the problems with "classic" controllers, commonly used in other fighting games, but they're considered unfair or even cheating by a lot of folks?
@danluu The rabbit hole on this actually goes pretty deep...
To do a dashback (high-level mechanic), you need to move your stick from neutral to fully left/right within a frame. This is very inconsistent because the game can poll for an input when the stick is ~halfway. So what you _actually_ want is a controller that occasionally drops inputs (a not-uncommon manufacturing defect, but luck of the draw unless you buy one at a premium), so the game sees the stick move to the edge instantly.
@danluu Non-official controllers (digital or otherwise) solve these problems and more. But of course, a good chunk of the community wants all non-official Nintendo controllers banned for the sake of purity or something.
...*except* to account for the inconsistency of dashbacks and similar mechanics, there's a mod that's common at tournaments (UCF). So why not just allow alternative controllers that give you the same benefits without the headache of modding the game?? 
Dan Luu
Kyle Lacy
meduz'