I would recommend the "Jewel Class" ships. Jewel, Gem, Pearl, Jade are excellent ships and made for Freestyle. I've sailed on Jewel, Jade and Pearl and they are some of the best cruises we've done. The Dawn and Star are a bit smaller but still made for Freestyle and I've sailed both and enjoyed them. I don't know why though but the Dawn and Star are the only ships I get "lost" on.
It's just how their, I believe, deck 6 is arranged.
Overall; NCL is my favorite line to sail and I am proponent of Freestyle Cruising.
I love all the restaurants and the diverse and interesting entertainment on Epic. You will NOT be bored on this ship but I personally do not like the ship itself. It is actually the least favorite "ship" I have sailed. I don't like the cabin layout. How the traffic patterns are geared to channel you to Deck 6 and it always seemed crowded as did the pool decks. I loved what the ship contained but I did not like the ship itself.
I'm looking forward to the Breakaway ships. It looks like NCL took what was good about Epic and Jewel class ships and put them into these two new ships.
The only other word of advice is to add $100 - $150 to your cruise budget and partake in at least two or three of the specialty restaurants and get the most out of the Freestyle experience.