"If I were to say one single reason for our change, it was that we needed tight integration," said Flora Sun, chief operating officer at Adina for Life Inc. in San Francisco. "We needed fully functional end-to-end processes."

In April, the beverage maker switched from Salesforce.com and a mix of accounting and inventory systems based on Excel, QuickBooks and homegrown applications to an integrated system hosted by NetSuite Inc. Previously, Adina had tried to dovetail Salesforce.com and its other applications "by doing jury-rigging," Sun said. "It was just very laborious, and we constantly had to have someone watch over it."

Portland, Ore.-based Learning.com cut over from Salesforce.com to NetSuite last September in order to get an accounting system that was tied to CRM applications, said Douglas Stein, vice president of technology and development at the provider of online educational services.

The license fees charged by the two vendors are about the same, Stein said, but he added that the change has resulted in a lower total cost of ownership. He estimated that Learning.com could save hundreds of thousands of dollars because it won't need to add technical staffers. Just avoiding the cost of integrating the CRM and accounting applications saved the company about US$60,000, Stein said.

Salesforce.com is taking steps to address the integration concerns. In January, the San Francisco-based vendor launched its AppExchange software marketplace, which lets users buy third-party applications that can be linked to their Salesforce.com systems.