I love this ballhead! I bought it for its compactness and light weight to replace a Kirk BH-1 ball head I was using. Although the Kirk ballhead is a great ball head, it was a little too heavy for my use. The Gitzo ballhead locks down tightly with very little pressure. I wanted a ball head with friction control, and I like the fact that the friction control is on the main knob (not a separate knob). My only complaint is that the friction control is a little too loose and easily changes its tightness.
Older generation of 80-200 2.8D (heavy) and D810 does not have any difficulties to be tightly fixed on it. Friction control allows me to fix my cam in an angle without tightening the knob, it is useful especially when i need to change my angle of view constantly in the conference or seminar.
Unlike the earlier one that I received with over tighten safety pin, I have no problem to remove the safety pin/scew and it works nicely with my RRS L-plate and sit nicely on my Gitzo traveler tripod.