I booked this cruise on 12/28/12 for my 79 year old mom with dimensia and who uses a wheel chair for ease of mobility. I sailed with my in-laws and Dad on the Freedom of the Seas in December and had a great experience.
I chose the Liberty for a few reasons. One is that the ship is easy to get around on with a wheel chair. There are other ships like the Majesty that require lots of elevator changing to go to certain levels or you have to go all the way to the pool deck to cross the ship. Somewhat inconvenient and I didn't want to have to deal with that so I chose Liberty.
I also chose Liberty because as a Diamond member on Freedom, they reserve the Chops Grill for breakfast and lunch and provide table service for coffee and juice and you just go to the Windjammer for the food. Having to push the wheel chair and get drinks, then food seemed like too many steps and I would not have had that room available on the Majesty. Mind you we drive to both ports and Miami is an hour and Port Everglades 40 minutes from our house so either port would work but again I chose Liberty because of these amenities.