The interview was a full day event with lunch included. The morning was set aside for interviews with the Director of Engineering, Manager of the Hardware group, and mostly 2-on-1 interviews with the development team until about noon. Everyone I spoke with were very knowledgeable and personable. A well put together and cohesive team. The Software Development manager was reasonable and someone who I could work for. The products and the applications were interesting and felt that my skill set and career would have grown. I had a really good feeling about the company after the initial phone interview and the one on-site.
The afternoon was set aside for testing. There were many tests, which included IQ, numbers and words matching, pattern recognition, personality, and one directly related to embedded development. It was pretty exhausting.
There were several idiosyncrasies that one may find with most private companies (i.e. require that lids are on mugs, everyone parking in the same direction, etc..). During this time, they were recovering from flood damage by recent heavy rainfalls, so the facility wasn't too appealing; however, they were also in the process of moving to a larger one. I never saw the new facility on the inside, only from the outside. Engineers are in large cubicles and are doubled up.
It is a very established private company that has been around for quite some time. If you're looking for stability, then you'll appreciate this company.