As far as I’m aware FCP-X does indeed have metadata fields. In fact it has loads of them and even the option to create your own fields and custom field views.
Click on any clip and click on the ‘Info’ tab on the far right, next the audio and video tabs. At the bottom of this box are options to switch views, create custom views and fields.
My big issue with these fields are that none of these fields appear to be searchable (either globally or individually), so it renders their useful pretty close to zero.
If they were searchable it would be fantastic to be able to export clips from CatDV to FCP-X and map metadata from the CatDV into existing or custom designed fields.
Terry