This site's video about HCG warns that using during a cycle is bad due to an increased chance of screwing up your test production post-cycle since you become dependent on the HCG effects.
Yet the sticky in this forum suggests using HCG during cycle.
What is safest for returning to normal post-cycle?
STICKY: "hCG is vital if you are concerned about recovery. In short, it will prevent testicular atrophy, maintain your natural testosterone production (Because steroids shut that down); thus resulting in a healthier and a more speedy recovery."
Site HCG Video:"The problem with this type of therapy is that it can easily lead to a permanent low testosterone condition. (...) The body can become dependent on the LH mimicking effect provided by HCG."