In all factors measured in the study, customers with connected home devices have higher satisfaction than those who do not, with the gaps most pronounced in the features factor. Features satisfaction is 74 points higher among those who have voice-activated home assistants than those who do not (861 vs. 787, respectively). Among features attributes, customers who have connected home devices provide notably high ratings for a variety of phone file formats and a variety of additional content available, since connected home devices provide access to additional smartphone functionalities.

"Customers with connected home devices are able to improve the comfort, convenience and security of their living spaces with their smartphone devices," said Kirk Parsons, senior director and technology, media & telecom practice leader at J.D. Power.  "They are more satisfied with their smartphones because they can take advantage of smartphone functionalities that other customers may not be aware of. Smartphone manufacturers that make it easier for their products to connect with other devices will have a major advantage in improving customer satisfaction as homes become smarter and more automated."

The frequency of smartphone use for connected home devices also affects smartphone satisfaction. Customers using their smartphone daily in such a manner have much higher satisfaction than those who use their smartphone less frequently for smart thermostats (926 vs. 866, respectively); smart appliances (929 vs. 851); and voice-activated home assistants (928 vs. 878).

Following are key findings of the 2017 study:

• Overall satisfaction rises: All ranked brands have seen improvements in overall satisfaction during the past year, with Motorola (824) showing the greatest improvement since the 2016 Vol. 1 study (+15 points), followed by HTC (+12 points) and Apple (+6 points). Most of these gains came since last volume, in which Motorola, HTC and LG improved by 22, 17 and 14 points, respectively.
• Carrier-level satisfaction differs: Among carriers, overall satisfaction with smartphones is highest among AT&T customers (841), followed by Sprint (840), Verizon Wireless (831), U.S. Cellular (829) and T-Mobile (828) customers.
• Connected home incidence differs: Customers whose smartphones have iOS have slightly higher incidences than customers whose smartphones have Android of owning smart thermostats (13% vs. 11%, respectively); smart appliances (9% vs. 8%); and voice-activated home assistants (7% vs. 6%).
• Brand loyalty matters: Customers who are more satisfied with their smartphone are better brand advocates than those who are less satisfied. Among customers who are delighted (satisfaction score above 900), 73% say they "definitely will" recommend their smartphone brand. That percentage drops to 40% among satisfied customers (satisfaction of 750-900); 13% among indifferent customers (satisfaction of 550-749); and just 7% among dissatisfied customers (satisfaction below 550).
• Shifting away from subsidized phones: The shift away from phone subsidies in the full-service segment contributes to the rise in the average smartphone price of $366 from $361 in 2016 Vol. 1 and $318 in 2016 Vol. 2