I generally find these products useful, and the behemoth and the ghost are both exactly what I need more of for my campaign - I have players who can routinely make the difficulties involved (or ignore environmental hazards entirely). My current group has armies at their command, and having massive monsters for their Tiger-Warriors to face is great. I don't feel that for my game they are 'over-tuned'.
As for the NPCs in Adversaries - all of them have had useful stories, interesting hooks, and generally meant that I have people I can slot in when I am feeling a little low on creativity. So,...