I use evrything equally in the game for a balanced empire of monkeys. Especially when you rank up in the game for al;l the upgrades! I've unlocked them all since i'm rank 39. No cheats.
My friend got to level 94 without cheating on BTD4!!!!! I'm not kidding! I swear to god i'm not lying!!!!!!!!!! He did it!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!