Comparing ACS Per Capita Income and BEA Personal Income

Can anyone point me to discussion of the differences between ACS per capita income and BEA personal income.

I realize the differences, which can be startling to the unfamiliar, reflect how the numbers are measured. I need to explain this to several financial people who are unfamiliar with both data series but have been using BEA figures in a particular document. I want to convince them to switch to ACS numbers, as they are a better fit geographically.