Which cruise should we pick?

[happytime]

I would definitely go with the 5 day over the 4 day. The 4-day is too short! Have fun and enjoy your cruise.
If you fly into FLL, I believe you can get shuttles (cost $15 pp) that will drop you off right at the Port of Miami. Done.
I wouldn't stay in a Miami downtown hotel as I wouldn't want to walk to the port, rental car, or hotel lugging my suitcases behind me. No thank you. (former flight attendant talking--no more lugging suitcases behind me unless I'm in the airport. lol I would easily consider a fly into FLL, stay at a hotel near that airport, then arrange to take the river boat cruise near the Port (Everglades) for a very fun night. The river cruise includes dinner and entertainment.

 

[Ragnrok23]

I should add I'm flying in from Rhode Island, so we are flying in the night before just in case of any delays, that's why we would have a hotel stay either trip

I was thinking 2 nights at WDW hotel just to keep the trip the same length, maybe do DTD on our full day

 

[Fyrefly]

I'd be tempted to say the 5 day. You know your kids best but I feel like more time on the ship to play would be better than being in sight of a park but having to do a shopping day instead and not being allowed to go in.

 

[BruinEd03]

I would do the 5 night cruise. We did a 3 day Disney World trip before a 4 day Disney Cruise and it didn't feel quite as relaxing. We felt like we had to pack up just as we unpacked and then moving from Orlando to Port Canaveral was also a bit of a hassle.