I agree with the previous response - to each his own. I personally know that my husband and I have a limit of two, the beautiful little boy and girl we have now. We feel our family is complete. But some people thrive in a large family. I think that the main difference between the Duggars and "OctoMom" is that the Duggars clearly have the means to support a family that large both economically and emotionally. They have crafted the arts of thriftiness and order (organization). The children and extended family seem to be truly happy. Their religious and personal beliefs seem to play a huge part in their choice to continue to grow their family. They have created a wonderful support system within their family so I see no problem with what they are doing.
As far as OctoMom goes, 8 of her children are babies of the same age and previous children from what I understand have some disablilties that must have already made life a huge challenge. She is a single mom raising all those children and I believe that she does not have the means financially to do so, or the manpower for that matter. None of her children are of an age where they can be expected to help out without feeling taken advantage. Octomom does not appear to have stability, even her own mother speaks out against her which is neither a good testament to Octomom OR her mother. I do not have a problem with artificial means of conception, but I do have a problem with a woman who doesn't seem to have her act together bringing 8 babies into this world via the method she chose. Single mothers are entitled to stay single, but raising a family is alot of work and is not a joke.
Bottom line is Duggars = peace and happiness and teamwork and Octomom = stress and chaos and pity.
I do not worry about the Duggar children, but to think of the future mental health of the Octomom kids is scary.