A gas-powered lawn mower offers several benefits over an electric one. For example, the increased power allows them to easily cut through longer/tougher grass, and they are not limited by cord length or how long the battery lasts.
A self-propelled lawn mower requires less effort from the user, as you don’t have to manually push it forward.
Cordless tools/machines are suited to a variety of different situations, as you are not limited to only working in places with power sources nearby.
A larger collection bag means you have to empty it less often, and is particularly important with a larger lawn.
A rotary mower cuts the grass with a blade or disc that rotates on a vertical axis. They have the benefit of requiring little maintenance, and are often cheaper and more lightweight than, for example, a cylinder lawn mower.
A steel deck’s main advantage is that it is durable, and if you hit a stone it will only make a dent rather than fracturing.