I have a Griffin vise, and it is a very reliable company, that stands by it product.
I have a Renzetti, that I am using, I have both the regular vise head, and the tube fly vise head. The company seems to have a Public Relation problem with anyone that makes rotary vises, that are similar to the Renzetti, because of Trademark issues (not to be confused with Patents, which is something different).
I have tried the Danvise, and really like its setup and operations, for $80 you cannot get a true rotary vise for less money. Very good value.