I applied through college or university. The process took 5 weeks. I interviewed at American Express (Fort Lauderdale, FL) in Feb 2015
Interview
Two Rounds on campus of mostly behavioral and some easy technical questions. Three rounds on site about a month later in Ft Lauderdale. Same story, mostly easy behavioral questions with some easy technical ones. The most important things to prepare are good answers to the behavioral questions. I think the interviews are becoming more technically rigorous, however. Especially for full time.