That's a great question, and the answer depends a bit on what you're cleaning up. If you're dealing with loose debris like leaves, dirt, or bird droppings, slatted benches are actually surprisingly easy to deal with. The gaps allow a lot of that stuff to fall through naturally when you sweep or spray them. A quick blast with a leaf blower can clear them out completely in seconds.
However, the solid seat wins for liquid spills. Think of a spilled coffee, rain, or melted ice cream. On a solid bench, you can simply wipe it down with a cloth or squeegee, and the surface dries evenly. On a slatted bench, liquid tends to seep into the gaps, get trapped underneath the slats, and become sticky or moldy over time. You might need to individually wipe each slat from multiple sides to get it truly clean.
From a long-term maintenance perspective, solid benches are often considered easier for municipal crews. They can be pressure-washed directly without worrying about water being trapped between slats. Slatted benches, while great for air circulation and quick drying after rain, often require a brush to scrub the dirt that gets wedged in the grooves. So, for a quick daily clean, solid seats win; for a once-a-month deep clean of loose debris, slatted benches are easier. If you want the best of both worlds, look for benches with wide, rounded slats that have large gaps—this minimizes trapped debris while still allowing water to escape.