Cajun for me--got 37 of them in use (one for every spool of serving), plus 10 or so spares. I like to add some extra weight to them--self-adhesive wheel weights (ala Rod Jenkins), or switch out the bolt for a longer one and add fender washers.
I've tried dang near every one I could find at one time or another (except the Beiter--I can't see $45 for a serving tool), and the Cajun (Bayou) has worked best for me. Still have the first ones I bought, and they are still working fine after several thousand strings.
Chad