Leap Slam is primarily used as a movement skill. It is one of three skills that allow you to cross cliffs, chasms, and obstacles without prior preparation, the others being Lightning Warp and Flame Dash. How to use Flame Dash?
Accuracy: Accuracy is a factor despite the nature of the skill. Leap Slam can miss.
Attack speed: Leap Slam has its own attack time of 1.40 seconds and modifiers to attack speed will modify the speed at which Leap Slam performs.
While its base attack time is not equal to the base attack time of your weapon, it does benefit from local attack speed modifiers on the weapon just like any other skill (multiplicatively). Having enough poe exalted orb can make things easier.
Leap Slam may seem slow when jumping small distances, but in reality, Leap Slam is simply always performed at the same modified speed regardless of the distance jumped.
Dual wielding: Leap Slam will use only the main hand weapon.
Damage: Tooltip incorrectly averages the DPS and APS of your Main and Off Hand weapons, even though only your Main Hand weapon will ever be used. This is true even if your Off Hand weapon could not be used with Leap Slam in the first place.
This will give you a reasonably close approximation, as your chance to hit may vary between your main and off hand but is averaged on the character screen.
Multistrike Support: Leap Slam cannot be supported by Multistrike.
The maximum jumping distance of Leap Slam is confined by a square rectangle centered around the attacker. This means that the actual maximum distance will be 2 times as long, roughly 41% longer, jumping diagonally as it would be jumping straight up, down, left or right.
Since the duration of the jump is the same regardless of distance, you will also end up travelling about 41% faster that way. Flame Dash and Leap Slam seem to be the only two skills that work this way, all other skills have their max-range defined by a circle as one would expect.