The thing I didn’t like about the X3 was Clayton’s decision to use a 12” driver to reproduce the midrange. I never got the feeling that the midrange reproduction seemed “real”. There was no texture to voices and instruments. Dynamics were good and the bass depth and quality was excellent. I kept them about a year and moved them on.
It’s been a while, so hard to compare. The midrange performance of the IQs is definitely top notch. The powered 15” drivers on the X3 might get the nod, but not by much.