The more strokes per minute the faster a jigsaw can cut, but there are other factors that contribute as well. The stroke length is the distance the jigsaw's blade travels up and down. The longer the stroke length of a jigsaw, the faster it is able to cut. This is because more teeth come in contact with the workpiece per stroke. - MitchellMc
Higher speed potentially faster cut but depending on what you are cutting and blade type not necessarily an advantage. Stroke length determines how thick the material is you can cut. - JDE
The Ozito Cordless System uses a system called Power Xchange. When you buy an Ozito tool with this system, it allows you to use all the Ozito Cordless tools with one battery. It's very convenient, versatile, and frees you from having to attach to a very long extension cord. If you purchase the Ozito PXC 18V 2.0Ah And 4.0Ah Lithium-Ion Battery And Charger Pack this allows you to finish a large number of D.I.Y. projects. It also allows you to build your tool chest without having to purchase a battery pack for each tool.
However, some Ozito products come with their own battery and charger like the Ozito PXC 18V Drill Driver Kit. These packages save you money by selling them as a set rather than buying the battery and charger separately. It is a smart first purchase if this is your first tool. It now allows you to consider the other Ozito Tools and purchasing them as "skin-only" with no battery or charger included. As long as it has the Ozito Power Xchange logo on it, rest assured the Ozito battery will work with that tool. - EricL