Dart Monkey: Left is for when you place your monkey in a straight line, right is good for beginning rounds (if you have 10 nearby each other, the ability is OP against regular MOABs). Tack Shooter: Left because covers better than Right, and is more effective against MOABs. Sniper Monkey: Left because it is more effective against MOABs (4/2), but right (2/3) is good against getting rid of those pesky fast Bloons, otherwise right (2/4) is bad (who needs $400-1500 on round 70 and up?).