Hi Bennie Weenie,
Definately do the NCL Gem itinerary. As Paul says they are great locations as we did all of those on our med cruise in August (obviously in the heat then).
You will get to see so much more of Europe and the different countries that way.
As we speak, our US friends are actually on the Gem now having sailed from Barcelona on Monday and they are doing the transan to Boston.
I have heard from them and they say the ship is great and having a great time.
Barcelona is a fabulous city. We spent a long weekend with them last weekend post cruise and they live in both Scottsdale and Chicago spending 6 months in each city. They both absolutely loved Barcelona and are planning on sailing from there again so that we can all spend a long weekend there post their cruise back to the US
So if it were me go with the NCL Gem.
When they have arrived in Boston and I can speak to them once they get back to Az. I will ask them their thoughts after the 12 day cruise and let you know.