Of our party of 7, three of us were in the Haven area (room 14014), two were in an inside room on the 11th deck and two had a mini-suite on the 11th deck. The couple in the inside and the couple in the mini-suite had no complaints about their rooms. Both couples thought their rooms and stewards were very acceptable.
Daughter #1, husband and I, however, really lived the good life in the Haven area. What a great room (actually 2 rooms)! We had a good-sized bedroom with king bed (most comfortable bed I have EVER slept in!) separated by curtains from an amazing bath with tub, separate shower and separate toilet. Tub and shower had windows - what a view on sea days! Adjacent to the bedroom was an equal sized room that held a living area with couch/bed (slightly smaller than a twin when made up), 2 chairs, dining table with 4 chairs, plus a bar area with fridge, counter, glassware and dishes. There was also a smallish balcony with 2 upscale chairs and a small table. The two room were separated by a solid sliding door. Storage was everywhere and plentiful. A fresh flower arrangement, bottle of champagne and bowl of fruit were in the room on our arrival, compliments of NCL. Very nice! Our staff included Roel, our butler, Florentina, our concierge, and Michael, our steward. I can't say enough about all of them. We used their services many times each day and their willingness to help never diminished! Wonderful people.
The Haven area itself is very nice, with cushy lounges, sofas and tables and chairs. There was a continental breakfast there every day at 6 a.m. with coffee, juice and pastries; and snacks later in the day. We also had a Haven cocktail party on day 2 with passed appetizers, champagne, wine and soda. The captain and several top crew were present to talk with passengers. Elegant start to the cruise. The Haven pool is very small - really just a plunge pool and heated a little too warm. There is also a hot tub, steam room, bathroom and small gym in the area. Plus a private sun deck with double-sized hammocks and double-sized lounges. Very quiet and private. Of course, there's also a butler just for this area in case you want a meal or beverage!
I'm sure I'm forgetting other amenities to the Haven - there are so many!
Overall, I would sail the Gem again just to stay in the Haven.