I've got both items: a Flymo rotary mower (with cuttings collection box) and a Flymo Multitrim trimmer. The mower can get bunged up with damp grass cuttings at the place where it discharges into the box. The trimmer (it cuts with a plastic cord) does not have that problem with damp grass. The semicircular guard around the plastic cord does get a buildup of grass cuttings inside, but the cord just slashes its way through them and it keeps on going. It cuts the grass whether it's damp or dry.So a trimmer would be better in that respect.