We just got back from cruising on the Epic in the Mediterranean. We had a good time. Embarkation and debarkation were a breeze, easiest time we have ever had getting on or off a cruise because there wasn't hardly anyone getting on or off the boat in Rome. Most people get on or off in Barcelona.
I wasn't sure I would like the Epic because it was so big, but the only time we ran into a lot of people was in the evening. One night there was a long wait to eat in the Manhattan dining room so we went to one of the other small restaurants. The staff was really nice and friendly. They had a lot of air cleaners in the casino and that helped keep the cigarette smoke down. I liked the bathroom setup, even though I came on board with an idea I probably wouldn't care for it at all. With the sink, shower and water closet broken up we didn't have to get out of the sink area for someone else to take their shower or go to the rest room. Also you step out of the shower and have plenty of room to dry off, which was an added bonus I had not expected. There was a lot of storage and hangers in the closets.
You can sign up for entertainment shows like the Blue Man Group as well as the restaurants and excursions on your TV, which was a great feature. No more standing in lines at the guest services desk. They also had boards on the boat that did the same thing, but they didn't work very well if you used your finger. Using your fingernail to make your selections take better.
We only went on one of the NCL excursions in Barcelona and after having a private tour guide it wasn't as much fun. We mainly used Rudy's Rome Tours (http://www.rome-car-tours.com/tours-from-ports.htm) and I highly recommend them. They picked us up at the dock when we got off the boat and we saw more in a day than we would have seen any other way. The price is very reasonable, about a 1/4 of what NCL charges for a private tour guide. We liked it so much we recommended it to another group on the Epic and when we met up with them they said they were having a great time, too. Rudy's service is not just limited to Rome and I would recommend you contact them prior to your sail date to schedule the tour. He is very responsive and will email you back quickly.