I have had both. I also have a 20' Wooldridge with a bunk trailer, that has slides on the bunk. I have never cranked my boat on, so I have no idea what that would be like. I just drive it on until I hit the post or just short of it.

Edmonds charges more for the bunk, but if you cut the bunks for the sling, then price is the same as a roller trailer.
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"90% of Life is just showing up and doing the work". Tred Barta Sr.