Welcome to the NCL forum.
The main difference between NCL and RCCL is NCL's Freestyle Dining.
There are no early and late seatings for dinner at the Main Restaurants, and the dress code is Resort Casual every night. You can dine early one night, and late the next without setting up reservations.
But, if you plan to dine at the Specialty Restaurants, some of which have a surcharge and some don't, you should set up reservations, as they are small and popular. My best hint is to book these reservations early. You can book them by phone, at the restaurant during that day or the day before, or at the main reservations counter near the main lobby or atrium.
On the Sky, here are the restaurant choices:
Four Seasons Main Restaurant(Main Dining Room)
Cuisine: Continental
Dress Code: No shorts after 6:00 p.m. in the dining rooms.
Surcharge: No
Reservations Required: No
Seven Seas Main Restaurant(Main Dining Room)
Cuisine: Continental
Dress Code: No shorts after 6:00 p.m. in the dining rooms.
Surcharge: No
Reservations Required: No
Horizons Trattoria
Cuisine: High-end Italian
Dress Code: No shorts after 6:00 p.m. in the dining rooms.
Surcharge: Yes, $12.50 per person
Reservations Required: Yes
Le Bistro French Restaurant
Cuisine: French
Dress Code: No shorts after 6:00 p.m. in the dining rooms.
Surcharge: Yes, $12.50 per person
Reservations Required: Yes
Ciao Chow
Cuisine: Italian & Chinese
Dress Code: No shorts after 6:00 p.m. in the dining rooms.
Surcharge: Yes, $12.50 per person
Reservations Required: Yes
Garden Cafe/Great Outdoor Grill
Cuisine: Assorted Buffet, Food Stations, Snacks & Grill
Dress Code: Casual
Surcharge: No
Reservations Required: No
There are also 24 hour Room Service , and a Lido (pool) Deck Bar-B-Q most afternoons.
The other major difference, besides the facilities aboard the ship between NCL and RCCL, is how they handle tips.
RCCL hands out envelopes the last night with recommended guidelines that add up to $10 per day, NCL charges $10 per day per adult passenger automatically to your on board account. You're free to tip more for exceptional service on both cruise lines.
Presently, NCL has a promo for kids sailing free (no fares charges, but still charging for taxes and fees).