I interviewed in Cambridge, having recently finished a PhD. Communication was effective, though sporadic. The overall process took approximately 4 months, though holidays and my own schedule got in the way somewhat.

I had two days of interviewing, with two technical interviews each day and one thesis discussion. My overall impression was very positive: the interviewers were interested to see how I think and were encouraging and supportive when I hesitated or wasn't sure how to proceed. Half of the interviewers had more of a "professional" appearance, and half had more of a "hacker" appearance.

Questions ranged from basic "write this recursive function" to more open-ended "start designing this type of system, even though obviously you won't finish in 45 minutes." Nobody was super picky about code style or being a Java know-it-all, but emphasis was placed on being able to write clean, clear, maintainable code.

An open-ended question was posed about designing an interesting 2D puzzle. The core requirement was "interestingness," which was left open to the interviewees' interpretation.