There is not much difference in functionality between a normal slide in range that includes both and oven and a stovetop and separate appliances like a wall oven and a cooktop range. However, the cooktop range and separate wall oven will have a unique appearance that is sleeker and more customizable. You can purchase a stovetop that blends with your counters and a wall oven that blends with your cabinets.
Wall oven manufacturers recommend that you place your oven 32 inches above the floor. This placement, however, is for convenience rather than safety. This placement allows you to lift food in and out of your oven safely. The oven manufacturers generally require at least 2 inches from another appliance. Check with your manufacturer, however, for more specific requirements.
Under Oven Support
Wall ovens are quire heavy and are meant to be installed in a strong cabinet with a cavity that will support the weight of the oven. If you put wall ovens low in the cabinet, you need to ensure that there is a cabinet platform under the oven that will support the weight of the oven. Wall ovens can weight up to 300 pounds depending on the make and model.
Countertop ranges have various requirements for installation that will help prevent fires. Cabinets should be at least 18 inches above the countertop. This gives adequate clearance for tall pots. The drop in stove has to be at least 6 inches from any walls and at least 1.5 inches from the wall and 2 inches from the front of the countertop.