I've got a cheapish 3 way video type head that came with my Velbon tripod.
I found that this moves too much aften tightening especially with anything heavy on.
When I started trying to take moonshots by digiscoping it was almost impossible to lock on to the subject.
I'd end up with the end of the lens about 6 inches higher than it should be to allow for the droop that inevitably followed.
Everyone on the Nikonians site rave about how brilliant the Markins M10 ballhead is so I bought one of these.
They are really good BUT you can lock the ball in position and pan but it's a real pain trying to keep the camera on a true horizontal plane when the head is adjusted to allow for general moving. The camera and head can move off the horizontal axis with the slightest movement down to the left or right.
Someone recommend me a head that can do everything smoothly and lock into position perfectly with no droop etc afterward.
If there is such a thing