I just did a b2b. It's very cool...for about an hour or two you feel like you own the ship!
Especially if you don't have to change cabins. The one I did, the only thing was that for a while you can't get into your cabin, so pack a bag and enjoy sitting by the pool and being the first one in the lunch line!
We did this last year and had to leave the ship for 2 hours. They say it was for US custom requirement. We left everything in our cabin and just took our ship documents and passports.
We are thinking Celebrity Soltice to Ruby Princess...out of Ft. Lauderdale...4-17-2011 > 4-24-2011...to... 4-24-2011 > 5-1-2011...The more I think the better it sounds... Any advice on changing ships...even though the same port?