iPhone manufacturer Apple ranks highest in overall customer satisfaction among business wireless smartphone users, according to the J.D. Power and Associates 2008 Business Wireless Smartphone Customer Satisfaction Study.
The study, now in its second year, measures business customer satisfaction with wireless smartphones—defined as mobile phones offering advanced capabilities and personal computer-like functionality—such as a BlackBerry or Treo. Overall satisfaction is measured across five key factors. In order of importance, they are: ease of operation (27%); operating system (24%); physical design (21%); handset features (18%); and battery aspects (10%).
Apple ranks highest in overall smartphone customer satisfaction with a score of 778 on a 1,000-point scale, performing particularly well in the ease of operation, physical design and handset feature factors. BlackBerry manufacturer RIM (703) and Samsung (701) follow Apple in the rankings.
Via this J.D. Power press-release.

I am pretty sure consumers would also rank the iPhone and Apple very high in customer satisfaction.