I have used these drills for plastic and metal. Both seem to go really well with these beats. That happens pretty quickly, just think of the oil on the metal! I don't know how long they will last but I haven't seen any wear in the few uses I've used them for. The punch was a nice addition. It's very useful for various applications and to be honest I've used it more than just bits so far. The spring-loaded punch is great for marking drill bits, especially when approaching from odd or awkward angles.