Went on the Sep 7 to 14 Western Mediterranean cruise; had a really fantastic time and would like to share some thoughts and tips. Embarkation is very easy, if you like the silk scarves with Picasso motif from the souvenir shop but them then, as you won't find them anywhere else in Barcelona! Embarkation starts at 11am, you can wander round the shop and have lunch before the cabins are ready (wait for public announcement at about 2pm). Dinner at the specialty (payable) restaurants are buy 1 free 1 on the first night. We lunched mostly at the Garden Cafe for convenience (usually crowded) and dinner at Magenta which was less formal than Grand Pacific (same menu). Did not have to wait more than 10 minutes any one time. Food was good if not great. Lobster is served on Malta and Florence nights. Blue Lagoon is good for a light snack.
One of the most difficult decisions you will need to make especially if you plan to visit places on your own is whether to maximize you time in port, or have a workout and more leisurely breakfast. They allow you to disembark as soon as the ship is cleared (unlike lines which allow shore excursion passengers to go first).
We took only one shore excursion (Mt Vesuvius/Pompeii) as we figured out the public transport might be more difficult. Visited the other places on our own, manageable but a little rushed. Civitavecchia (for Rome) is very easy, and the train ticket includes all metro rides in Rome. Livorno (for Florence/Pisa) is far more complicated involving 2 bus rides and train. Bring plenty of coins for Villefrance to avoid waiting in ticket line as the ticket machines only take coins or credit cards (with PIN).