Leap Attack is a great skill for picking off targets one by one. It's particularly useful against those pesky Sand Leaper and unique bosses with the ability to Teleport. For those targets, just highlight your target and hold down the mouse button that Leap Attack is assigned to.
Once you get Leap Attack, you will no longer need to use the regular Leap skill. Also, Leap Attack has an extremely long-range from the very first point that you put into it so by using it, you're able to get out of sticky situations just as well, if not better, than with the normal Leap skill.
Leap Attack combined with Whirlwind can be an extremely deadly combination for your foes. Leap Attack can be used to get you into a good starting position for Whirlwind and it can also be used to help you escape quickly if Whirlwind is interrupted or if you run out of mana.
Hidden Knockback Radius
Leap and Leap Attack both have a hidden knockback radius associated with them. With Leap, it has a base of 2.6 (actually 2.64) yards and gains 0.66 yards per level. Example, a level 10 Leap will have a knockback radius of ( 1.98 + ( 10 * 0.66) ) = 8.5 yards. This is an approximation. With Leap Attack, the base knockback is 2.6 yards and gains 1.32 yards per level. Example, a level 15 Leap Attack will have a knockback radius of (1.28 + ( 15 * 1.32 ) ) = 21.08 yards. Leap Attack causes knockback to a monster, just like a Nef would do.