The worst sticks so far are the gc style replacement sticks from ebay.
People all over the world have problems with those like not being able to perform certain moves in Super Smash Bros.
This test really makes clear why:
Instead of solid lines like in the next picture these sticks just print out dots.
Which basicly means they skip steps, instead of 0,1,2,3,4,5,6,7 they do 0,2,4,6,8,10,14,18,22 or similar.