Guillotines cut paper with a large blade in a vertical cutting motion, and in terms of heavy-duty use, they score better than trimmers. Manual Guillotines can cut between 8 and 35 pieces of 80gsm paper in one cut, and whilst most will only cut A4 paper, several are designed to cut up to A3 in size.
Some manual paper guillotines have self-sharpening blades, and all should have blade guards to prevent you from cutting something other than paper.
At the top end, some paper guillotines have clamps to secure the paper to the cutting board. Many will also have pre-printed measurements on the cutting board to ensure precise and consistent cutting.