There is nothing, nothing, that compares with the Arca D4. I got mine on Charlie's recommendation and have not looked back. All ball heads drift, even the hallowed RRS, and they are quite excellent. I have used an old Arca B1, and still have and occasionally travel with an Acratech, but with the D4, you turn the knob and the camera stays EXACTLY in place, no drift. It is expensive and not super light but, like Charlie, I'd not be without it.