I got married on the Golden Princess in 2004. My wife and I loved it and wouldn't have done it any other way. We had my parents, her parents, and her brother and his girlfriend with us. I posted my experience when someone else asked a few years ago which I pasted below. Some of it is geared more towards Princess, but getting married at sea was a wonderful experience and I'm glad we did it. We've been to a destination wedding at Sandals, and while it was nice, I'm glad we did it on the ship.
Prior to the cruise, they are very helpful. You are assigned a wedding coordinator on land that answers all questions and handles the processing of everything and all the paperwork, vows, photography, videographer, flowers, spa appts, music etc... We had his email address and were emailing him constantly with questions. He was prompt to answer.
Once on board, we met with our onboard wedding coordinator. She confirmed everything, answered our questions, and gave us a walk through/rehearsal of the ceremony. It was so nice not really having to do or plan anything.
The flowers were really top notch and the chapel is very nice. They even had a ship camera so friends at home could watch (still shots updated every 60 seconds).
Everything went perfect. After the ceremony, we had our cake and champagne then we went around the whole ship with the photographer. He was fantastic and did a better job than the photographer we had at home when we had our reception. He took us all around the atrium, upper decks, etc... They even had a studio where we got some very nice studio pics. We even went in the bridge and they took some pictures there of us in the captains chair, and just us standing overlooking the water.
The package was fairly priced I thought -- we paid about $1000 for all the proofs, a number of 8x10s and 5x7s. We even got a canvas, and all the pictures on a CD. He even edited them all for us. If there was something we wanted cropped, etc... My wife wanted a B&W with just the flowers and he did this as well. All was included in the photography package.
I would highly recommend it and will definitely consider renewing our vows again on a cruise.
We did decide to have a reception when we got home (a few weeks later) so our friends and family could all meet and see us. We showed them all the pictures of the wedding etc...