I know that Fowler here on the board has one and seems to like it very much. I've seen his and it seems very well constructed. Mike Barranti makes a nice one also called the NW Hunter rig. I have one of his and love it for hunting just as another option. The turnaround time is not as fast as Ringler's though if that matters
"Better to Remain Silent and Be Thought a Fool than to Speak and Remove All Doubt"