It started with a general phone screen by HR. There were no technical questions except asking "How many years experience do you have with...", and no behavioral questions. Next, there was an on-site interview that consisted of two one-on-one interviews with other engineers. It was 100% technical. They did not open it up for my questions to them, and didn't even seem to consider that they'd need to sell the job to me. In fact, they didn't even ask me general questions - only questions from their pool of technical questions.
For this position (and maybe this would be different depending on the job), the questions were more on the academic side - questions touching on discrete structures, analysis of algorithms - generally the kind of thing that you need to know in school and don't really need in practice (and if you do, there's a book on your shelf for it).
It only takes one interviewer to pull the plug on you, so you have to impress every interviewer, not just the majority.