I've been a fan of Special Kitty Tuna flavored for quite some time, but
Bought a ChumKing recently and got a few tubs of their free chum at the Saltwater Sportsman Seminar.
They have and inshore and offshore type chum. Trolling etc use inshore, smaller pieces to dissolve and create a long chum slick. Offshore has bigger particle sizes to sink down to reefs and not float off too far, mostly a bottom fishing formula.
Nothing like being able to have chum shipped right to your door! Guess it would be best to try them all and see what works best.