They are great lives full stop. Kings, bonito, flat ties, big bream, jewies you name it and they'll probably eat it!
If you haven't kept them live which is likely, they go well as a fillet bait for good bream. If they are decent size garfish then take a slab off and use if on a snelled rig for jews.
I rate them very highly as a livebait and they go ok as a cut bait too.
Cheers, Tom