
This is one of the reason why you need to choose the proper head for your equipment. I believe many people use Manfrotto 501, 501HDV, and higher do not load it properly and adjust it properly and complain about the stickiness when start the pan/tilt.
That I concur with, I have seen complaints about the Manfrotto 50x series being sticky however my experience is with a heavier camcorder they work very nicely.
Wayne