The major difference between Complex PTSD and the regular variety, is that PTSD is usually developed as the result of one specific event or situation, whereas those who develop Complex PTSD have usually been exposed to trauma over a prolonged period, so that no one specific event can be pinpointed as the cause.
Complex PTSD tends to be suffered by people who have suffered from childhood abuse or domestic violence.
I personally view it more as a personality disorder than an illness, as the main problems it causes me are in my interactions with other people. I find it nearly impossible to open up and trust people. People with Complex PTSD are prone to insecure attachment disorders.
People with Complex PTSD have many of the same symptoms as people with PTSD, but also experience severe feelings of shame and guilt. They may also experience strong suicidal feelings.
Complex PTSD requires longer term and more intensive therapy than PTSD.
Living with PTSD (samaritans.org)
Complex PTSD (drkathleenyoung.wordpress.com)
Complex PTSD and the connection with anger (manyofus1980.wordpress.com)