Wife and I in our 30's went on the Epic the 24th-31st of March. We left the kids with Grandma. We were part of an extremely large group that took up 1/2 the ship. So we did not pick the Epic, it was picked for us.
We had a blast, I have read tons of these posts on Cruise critic so I knew what I was getting into. From a business stand point, I think the Epic is brilliant. IT'S DIFFERENT. That apparently after reading on this web site, change has freaked a lot of retirees and cruise addicts out. I think NCL purposely made the Epic different to stand out, to set it apart from the masses of cruise ships that are all very similar.
Differences: Best shows on the seas, free style, solo rooms, ice bar, no atrium, tons of deck rooms, style of the rooms, curves, bathrooms, showers. etc etc.