Different fibres in the matrix, get 10 different organics and you'll like as not get 10 different fibres, most will use different fibres within the same pad, some use sintered flakes, some use aramid (Kevlar) fibres.....
I appreciate your answers and help, but I just want to know the differences in performace and behaviour between "organic" and "ceramic" disc brake pads.
I already know that the composition is different, that is way too obvious. I want to know which ones make less noise, which ones are better for long descents, which ones are better for dry, and which are better for wet, etc... If there is anybody there who knows this please tell me, otherwise i will follow discobrakes advise and get the expensive ceramic pads.