The reason for that level of sucess is because it does better what it proposes to do, which is to be a good store of value and censorship resistant. Most other currencies try to do the same, but there is no way for them to achieve this being so centralized.
Bitcoin is so much special than the other currencies because the value of bitcoin is so good and have a good profit...compare to other currency..special because Bitcoin helps others unemployment and to other people want to invest..so i can say that bitcoin is much special compare to other currencies...Bitcoin is so great!