My wife and I are frequent cruisers, one or two cruises per year. We have cruised with RCI, Princess, Carnaval, Celebrity and NCL. This was our first trip on the Epic and we hadn't sailed with NCL in 20 years.
Embarkation was OK about 20 min. with no issues. We had a balcony room or as NCL called it a min suite (9257) on deck 9. The room was nice with comfortable bed and ample storage space. The bathroom is certainly different and has both advantages and disadvantages. It is an advantage to have the toilet separate from the shower however the toilet is basically in the room with only a frosted glass door and a curtain. The sink is even further into the room and is not blocked with the curtain. The toilet is very noisy and it is impossible to flush the toilet at night without waking up your cabin mates. I wasn't crazy about this setup but it wouldn't stop me from sailing on the Epic again.
The balcony was a good size with two chairs and two small tables. We were lucky with the room we had. Some of the balconies are not covered from above and balconies on deck 8 over look the life boots. So check the deck plans carefully before you book a balcony room.