They're great on X10s, but an absolute liability on ACEs. I was shooting next to a compound guy at the weekend who uses pins and ACEs, he says that he loves the fit of them but has to leave his arrows overlong so when he's hit the back of all of them he can chop them down and start again... Basically, the wall on the ACE isn't strong enough to take the force of the impact and so it tends to force the pin down into the shaft, which is a somewhat expensive mistake.
