After an initial phone interview, Illumina thought I was a good fit and called me in for an on-site interview. After the on-site interview (which consisted of several hours of 1:1 mini-interviews), HR stated that they would like to employ me on a contract basis (and after successful completion of the 1-year contract, offer me a permanent position).
The interviewers were great. They didn't make me feel nervous at all. I met about 8 or so people and each one had a different agenda. One wanted to get a feel for my personality, another gave me a riddle to solve, another relayed a scenario they had at illumina a few months ago and asked me how I would have handled it, another tested my knowledge of the technology, yet another went through my resume in deep detail to understand my background, etc.
No one in the interview panel was a jerk. I tend to get annoyed at technical interview questions (many have nothing to do with the position I'm interviewing for). When I did receive technical questions during the interview it was delivered in a personable way and I was allowed to ask questions to understand the problem--this was the key.