callaway x16 iron's any good?

Awesome. These were/are the king of forgiveness.

I'd have bought a set for my long-term experiment (don't worry, you've not been around long enough!) had they not had been so hard on the eye.

The X-18s are much better to look at i.m.o. but there's no difference in hitting. In fact, I can't tell you anything of any use (comparing club to club) between X-16/18/20 or even Big Bertha.

I paid £189 for X-18 3-SW.

Anything over this and they'd need to be in excellent condition or have new grips maybe.