I hardly acid spit as well. Usually only if I need to hit the other person on the other side of the screen really fast either to wake them up or to get the last hit in when I'm on danger. The long recovery is what puts me off from the acid spit.
I LOVE Reptiles acid spit, i think its actually really good vs people who like to play far back, 2 force balls and end it with a timed acid spit and on occasion you can catch them off gaurd. Or exactly what ABC said.
Reptile never has to leave the ground to keep a good game against Kabal, which is good because when people jump it's the perfect time for Kabal to counter with a spin. Forceballs keep Kabal pressured and one mistake on his part can lead to (possibly) big combos. Wiff spins will also lead to a big combo. Male Ninja's aaHP properties are good, so if a close range jump comes from Kabal he can be snuffed down.