Which is easier to maneuver, 25ft+20ft, or pickup+30ft FW?

Because a 5th wheel pivot point in above the rear axle and it tracks inside the wheel tracks of the truck, you cannot take as tight of a turn as a bumper pull. Think of semis that have to swing wide on tight corners to avoid jumping the curb.
With bumper pulls and the pivot point behind the tow vehicle, it lessens that problem.
Difference in trailer lengths also factors into the turn.