We went on the Explorer Jan 04in a word AWSOME this was my first cruise (to celebrate my 40th) and has been by far the best holiday in my life, the organisation by R.C I was great, the pre cruise hotel fantastic they even organised (without my knowing) a hotel post cruise day room for during the day to leave luggage, shower etc. because our flight was not till evening. the ship itself was the largest in the world. (before queen mary 2) wew were lucky enough to be among the first onboard that day so saw neer empty. i was told before going that a cruise is like a floating hotel, well this is like a floating town it has everything on it 3 tier dinning room 2 tier theatre, ice rink (the ice show is simply out of this world), minature golf, basketball, rock climbing, many bars and restaurants. The service was fantastic, treated like royalty rooms cleaned twice daily, several places to choose from to eat or free room service, there is 2 formal nights which are great where you are expected to dress up (if this not your thing you can dine elsewhere that nights)
they have a full programme of entertainment in the 'compass' published daily and you need to carry that around as there so much going on day or night, evenings you can choose from an international production show in the theatre or simple piano bar or the casino. and not forgetting the small part of the ports of call, we went western carribean which included haiti, Jamaica, Cayman Islands and Mexico.
I am not a good writer of reviews and would take too long to type a lengthy review which i would end up missing parts anyway, suffice to say this was a fantastic holiday, but please any questions on this beautifull ship please post. As i said that was our first but while on board i booked to go on the Splendour July04(smaller but the service was equally good) and while on board that we booked our next The Mariner of the Sea for March05 this is identical to the Explorer, which we are planning to revisit in 06 doing a back to back. sorry cant comment on the Navigator but try this US cruise forum site i 'm addicted to it
http://boards.cruisecritic.com/
scroll down and choose cruise lines royal carribean international, and once booked go to the roll calls and speak to others on the same cruise
hope this helps