The dining arrangements for crew differ from cruise line to cruise line.
Some of the larger lines have three options. 1) Officers Mess. This is for striped officers and equivalent ('un striped' crew such as shop manager, spa manager, cruise director and assistant etc). This is a more formal affair where patrons must be in the appropriate uniform. The menu is generally the same as the guest although there is normally a hot and cold buffet for those that would like. Wine is generally available depending on the line. There is an Officer Steward that will take care of orders. The people using this option usually have guest deck privileges, thus meaning they can use the guest outlets too.
2) Petty Officers Mess. This is generally for all those in guest facing roles. Shops, spa, casino, entertainment and some of the lower ranks in the deck and engine departments. A buffet is offered hot and cold normally the same as that offered in the OM.
3) The Crew Mess. For all other crew on board. Food is served buffet style. You can guarantee there will be boiled white rice at every offering. Self service all the way, although there are mess crew that make sure the area is kept clean, it is promoted that crew take pride in this area themselves.
In all three mess areas the food is varied and good. Generally a difference in all three rooms. Where possible the crew cooks try and cater to everyone's needs (we had a fellow Brit on one ship as crew cook, a shock to the system for him!), most of the time the food is fresh, sometimes you may see items on the buffet that were on the guest menu the meal before, eg. roast beef in the dinner buffet if it was on guest lunch.
A real treat is when the Asian crew host a night for all the crew. A wide range of dishes from all over the continent. Brilliant food.
On Medium sized ships, similar to that above but without the Petty officer mess.
On much smaller ships where space does not provide for separate galley areas for the crew; meals are taken before guest dining times, except breakfast which is a cold buffet (generally). This is more river vessels though.
As the menus are on a weekly/bi weekly rotation don't be surprised that as you are walking around your ports of calls if you see restaurants with large groups of young people..... Look closely and I am sure you will see some familiar faces (normally tried and tested restaurants too!)
Happy Sailing! x