i’ve tried pretty much every kind for trolling muskie lures: Scotty (and store-brand versions), Down-east, Ram plastic, Ram metal, and Folbe.
i’ve settled on the Folbe. yes, they’re more expensive, but i’ve been happy with the value they represent and it was a good investment. i’m running 4 rail-mounts, and 2 side-mounts. they are rock-solid with very little flex, are easy to adjust, you can get optional height extensions, they lock into place, and open very easily due to the design that puts rod pressure on the non-moving part.
if i was long-lining lures with less resistance, the metal Ram mounts would probably be my next choice, but planer boards in particular i like better on the Folbe.