But there are few more important points, so the fourth is the speed. This includes the speed of the jigsaw and the orbital action of the tool. Basically, the faster the jigsaw blade moves up and down the cleaner, the cut will be. So especially with bigger blades you always want to cut at full speed of a tool. Just remember that more speed = more heat. So for smaller blades, max speed is not always an option.
But nowadays jigsaws have the orbital action function usually with 4 different settings (0, 1, 2, 3). It makes the blade not only go up and down but also slightly forward resulting in a bigger bite. This allows for a way faster cut but at a cost of quality. 0 means the orbital action is off and 3 the orbital action is at maximum effect. As you see, the edges of the pieces will be rougher when using this function (last picture). So it is a balancing act to get faster and cleaner cuts.
On my jigsaw table, I almost always use orbital action. Without it is quite dangerous as you need to push the piece really hard and if your hand will slip, well you know the rest… Even the lowest orbital setting will provide a way quicker straight cut without almost no loss in cut quality (last picture). This of course also applies to all cuts when you using a jigsaw in your hand and not the table.
I use the 1-st setting if the workpiece edge needs to look good and for all other cuts, I lean towards the 2-nd setting as it is a great speed and quality balance.