Checking the dimensional information is important for all kitchen implements. It helps determine the layout of your appliances to allow for the optimum utilization of available space. For conveyor toasters, you will also want to check the size of the opening, especially the height, to determine how thick a piece of bread will fit.
Additional feature you may want to look for are an adjustable conveyor speed. Changing the conveyor speed will affect the number of slices you can do in an hour, but if your breads are coming out burnt or not even toasted, speeding up or slowing down the conveyor can alleviate this problem.