I have one, it does it's job. But I don't particularly like to use it. I have read, never witnessed it nor know anyone personally who has experienced it, that in the hard kickers that it kills wood stocks. Weighted down there's no give on the recoil end. The barrel and action thus slam your stock, I'd presume this to be worse at the tang. I could buy into this, but can't help but wonder if the stock is properly bedded that this wouldn't be an issue. I would not think that would be a problem for the 7-08 or other such calibers.
From my experience, there's no need to lug around the 25lb bags of sand or lead shot to use it effectively. 5lbs or thereabouts should do the trick.
My dislike about it is that I just don't like the shooting position it puts me into. It for all purposes extends the length of pull of your rifle and this puts me into an awkward position to properly see through the scope.