Let me first start off by saying that we stayed in a Spa Suite, which drastically altered our cruise experience.
PROS:
The benefits of being in a NCL Epic Suite are simply wonderful. You can literally cruise within the cruise. It's full of exclusivity - a butler, concierge, private areas, a private restaurant, lounge, priority embarkation & disembarkation, premium seating for popular shows etc.... Additionally, we had access to the common areas of an absolutely fabulous spa. The pampering is worth the additional cost (at least while on vacation :-). Customer service is A+ in those exclusive areas.