I've seen in a few threads that Hills Science Plan is not particularly recommended. That's what my 2 cats are on (fallen for vet's spiel?).
They have the adult light biscuits in the morning and half an adult light pouch each with hairball control biscuits in the evening. The latter does seem to have stopped my boy retching so much.
They are almost 4yr old Burmese/Bengal cross.
Is there something better?