The hardware works fine (including pressure sensitivity and the pen button), you just lose the proprietary Samsung apps. But, as noted in other comments, those

The hardware works fine (including pressure sensitivity and the pen button), you just lose the proprietary Samsung apps. But, as noted in other comments, those apps have their own issues, so they're no great loss. You're probably better off with third-party replacements even if you're not using CyanogenMod (e.g. Papyrus instead of S Note).