I'm looking for a mid size ball head & plate system like the RRS BH-40: http://www.butzi.net/reviews/rrsbh40.htm or the Kirk BH-3: http://www.naturephotographers.net/je0202-1.html Can anyone comment on them? Does anyone have personal experience with another brand? I'm concerned with size & quality -- I don't want a 40 ounce head or one one that slips ever so little as I tighten it. I'm very hesitant to order one sight unseen as the d**n things cost as much as my XTi did ! Thanks in advance.