[Fish]

I don't have any experience with it but it looks like the same system as the B&W companion.
If you don't already have a fifth wheel hitch I'd just get the B&W. If you do have a fifth wheel hitch that mounts to the standard rails on the unit you mention I'd get the curt x5 adapter I guess.

The only difference I see is that the 16210 (copied from etrailer website) Works with Curt Double Lock, Flip and Store gooseneck hitches

The 16220 (again copied) Fits Curt EZr Double-Lock gooseneck hitches.