Take any RRS ball head BH-55, BH-40 or BH-25 while your holding the camera for safety twist it loose about 1/4 of a turn and tell me what happens. You guessed it , it flops down right into the tripod which with heavy weight will do one of two things . Smack a body or lens right into the tripod or tip the damn thing over. I have seen and done both and reason I sold the BH-55. The Gitzo has and David can explain this better or Jack but you have to really loosen the knob like almost a full turn before this would be even possible. Also the cool thing is it will not fall over side to side only up and down because of the friction being applied is different than any ball head I have ever seen.
Guy, but BH-55 has that "open tension" knob that you can set to whatever friction-level you'd like for when the ball is fully "loose." So, I believe, you could set that tension knob high enough so that when you unlock the ball, the head doesn't just flop over.
Also, what you describe about turning the Gitzo knob is precisely one of the reason I got rid of it within a month. I HATED having to turn that knob around and around to get it to loosen up. I also had to really crank on it to get it to lock properly. Both of these movements, combined with the fine ridges on the knob made my hands unhappy, ESPECIALLY when it was cold out. I remember being so pissed having to constantly take off my glove, unscrew the thing, recompose, screw it down tight again, put glove back on with my roughed up cold fingers. Ugh, I sound like a weenie, but damn I hated that head. The ball movement in my particular head was never smooth either. Nothing like the RRS. There was always some amount of friction on it, and it never moved smoothly, it would just kind of jerk along. A smooth, but tight friction would be ok, but this ball just didn't have it. The RRS is just the ticket for my style I guess. I like the quarter-turn to full silky smooth movement back to full lock. It's just plain easy, but yes, you do have to have a hand on your gear when you loosen it.
Obviously, YMMV. My features are your selling points, and vice versa.
-J