Owners of e-readers such as the Kindle report they are happy with their devices according to a new study by The NPD Group. The majority (93%) of owners said they were "very satisfied" or "somewhat satisfied" with their device. Only 2 percent indicated any level of dissatisfaction. Features are important to e-reader owners. More than half (60%) said wireless access was their favorite feature on their e-reader and nearly a quarter (23%) mentioned touch.