What's the positives and negatives of HGH treatment?

Depends. If you are taking human growth hormone for a documented deficiency (pediatric or adult) the benefits can be proper growth and development for children, decreasing central weight, improved cognition and mood for adults. It should only be used when a documented deficiency is present. It can cause fluid retention, joint problems and Insulin resistance.
For what disorder ? Hgh is indicated in children with certain disorders that would stunt growth & in otherwise healthy children with short stature and in adults with growth hormone deficiency. In these patients, it can improve muscle strength and a sense of well being, & may prevent osteoporosis. However, it can increase the growth of certain tumors. Adults without growth hormone deficiency should not use hgh.