Anyone tried scope-gripps?

I have an 8" DSO dob and was looking for a counterweight solution when I ran across the scope-gripps at http://www.astronomy-shoppe.com/ and wondering if anyone has tried them? It looks like you can adjust the tension to accomodate heavy eyepieces or a binoviewer. I would be interested in how smooth motion is with tension set to a high level.
Thanks.

Dave Adams