Many of my clients are groups and associations. When it comes to their member directory wordpress needs, I highly recommend Connections.
One of its awesome features is the CSV imports. Many seem to struggle with the ability to import the file quickly. Hidden on the import page is a downloadable file for excel that helps you to have those items mapped. You can try over and over but if your file is not setup correctly. It is just going to wear you out!
Here is how you can make sure you have the Connections CSV Import.
But you can try either way.
All I know is it makes the upload and the Member Directory a SNAP!