iPhone maker Apple ranks highest in overall customer satisfaction among business smartphone users, according to a new J.D. Power and Associates study.

Apple received a score of 778 on a 1,000-point scale, doing well in the ease of operation category, physical design and handset feature factors. BlackBerry manufacturer RIM (703) and Samsung trailed Apple in the rankings.

"With the introduction of the iPhone in 2007, Apple has clearly differentiated itself from the competition in areas that are most important to business smartphone users," said Kirk Parsons, senior director of wireless services for J.D. Power and Associates.

"By making basic applications and features easy to use and providing functionality in a thin, lightweight device, Apple has performed well in exceeding customer expectations."

The study found that one -fourth of users experience at least one software problem with their current smartphone. The most common software problem is the need to reboot the phone, application malfunction and issues related to screen malfunction.

Among those who had a software problem, 44 percent report having to reboot their device at least once on a weekly basis during the past 12 months, while 34 percent report having either an application malfunction or an application freeze at least once per week.

"Given that smartphones are actual mini-computers, it’s not unexpected that users experience software-related issues," said Parsons.

"However, with the increasing number of features and applications that can be used on these devices, both the devices and software platforms will need to be more reliable if market penetration of smartphones is to increase over time. It’s critical for manufacturers to offer a complete package of functionality that is easy to use and has minimal operation malfunctions."

The study also looked at smartphone business usage patterns and found 69 percent of users own a hands-free headset, and 74 percent of those owners use a wireless headset device.

Among smartphone users, 37 percent would like GPS capabilities, 25 percent would like Wi-Fi capabilities, 23 percent want touchscreen and 15 percent would like to have voice recognition command for automatic dialing.

The top reasons for choosing a smartphone brand are, Internet capability (45%), ability to use email (41%), overall style (39%), Bluetooth capabilities (37%) and keyboard style (37%).