A good size and quite neat. However... If the top lid, instead of hinging to the back, was cut in half and hinged to either side, you could have two worktop areas to left and right of the central box.
Nice design overall. A few thing that give me pause though. The weight due to the thick plywood used and strength due to only broad nails and glue. Structural strengths can be overcome by using strips of wood in all the corners and weight can be solved by using 1/2 inch (12m) plywood for the outer case and 1/4 inch (5mm) for the dividers.