We went on the Emeral Princess in June 07 and used both restaurants. The food in sabatinis was lovely, but be prepared for lots of small dishes as your starters, they kept coming and coming as we thought they would never end. Then the main meal arrived which was lovely. The only downside in this restaurant is they don't know how to make a speciality coffee as they did not have fresh cream on board. Well worth the visit for a special occasion. The Crown Grill was superb. We booked ours on board - do not know if you can book on-line. Need to give both restaurants plenty of time for your booking.
Didn't eat in Sabatini's on the Emerald but did eat in the Crown Grill twice this year. Both times excellent - food and service. Once prebooked with another couple for a 40th Birthday and once when we just walked in because we didn't fancy what was on offer in the main dining room! No problems they seated us in about 10 mins! Enjoy!