I had an initial phone interview with one of the developers. He gave me a series of technical questions to gauge my level of knowledge and skill set. The conversation went well and I was asked to come in for a face-to-face interview.
I dressed slightly better than business casual (not too formal or overdressed), and was surprised to learn that the atmosphere was so informal. One of the interviewers even joked that I was overdressed and said "if you don't already own flip flops you need to get some". This could be a real good benefit for the right person.
I was also surprised to hear that they described their work environment as kind of harsh or abrasive. They asked if I had a thick skin or took offense easily, because some of the employees were known to have a short temper and to be rude.
I was asked if I wanted to proceed with working for them, but was never asked about my desired pay and was not given any indication of their budget for the position. Ultimately I didn't get hired and never hear back.