It was a group interview consisting of 5-6 people. Two hiring managers would interview the group and the questions were answered on a first come first serve basis. In other words, you don't want to answer last because most of the good answers would be said already. I dressed casually and still got the job. In fact, the one guy that dressed formally didn't get the job. They would tell you whether you got the job or not right then and there. The one guy that dressed formally was told to walk out and try again next year. It was a long process that took about 3-4 hours. Most of the time was spent waiting for the paper work to be done. Overall, it wasn't overly professional or too casual. It was handled as expected for the type of job I was applying to.