I took a day excursion on the 30-minute Ferry from St. Kitts to Nevis. The smaller, sister island to St. Kitts, Nevis very quaint with a decidely more residential feel [than St. Kitts]. Nevis is void of extensive commercial development and large scale, 'chain' hotels, restaurants, etc are scarse but the local people are GREAT. They are very friendly and unassuming. A number of small cafes dot the tourist area immediately off the ferry area. Beyond that however Nevis has the quaint feel of a small, welcoming town.
The beaches on Nevis are public. They are clean and the water is very warm and inviting. I took my swimsuit over and enjoyed a nice blend of tourists and locals mixing and revelling in the calm, clear waters.
Much of Nevis is unspoiled so nature enthusiasts should find much to like, from the vegetation and terrain to wild life. Given the steep hills on the island, there are probably fantastic hiking outings there. Whether you go alone or with someone else, I would advise guided tours versus car rentals because of the limited roads and hilly land.
Nevis has a limited number of hotels or resorts. Notably, however, the island is home to the luxury brand, Four Seasons Nevis one of the only Four Seasons Hotels in the Caribbean (Four Seasons Barbados coming soon!). If it's luxe you want, it's luxe you will get of course at the Four Seasons! Visible from the ferry ride from St. Kitts, the Four Seasons appears to live up to its reputation with its lovely beaches and exterior.
For more information on Nevis, visit Nevis's tourism site