Special Instruction vs. ABA?

august06mom

Can anyone tell me the major differences between these two types of things as related to ASD or PDD-NOS (DS2's dx). We need to choose which route we want to take, and I am getting such conflicting advice from his behavioral pedi and his EI people. DS has mild symptoms (almost all social), and ABA seems so strict.

 Any advice or experiences would be appreciated!