Personal opinion is that one type sold by SWB manufacturing is one of the best out there. One of their units is set up so that no one servo can overload and cause binding in another in the "gang". No loss of torque is encountered in this arrangement and it's simple to set up. Their "turn buckles" are very easy to install and adjust. I use one at each end of the wire to make things easy to deal with. If I can find it, I'll post a pic from RTK's Comp Arf that depicts the SWB unit.

Pat