Staff eng at large startup in Bay Area, 7-10 YOE. Recently interviewed at the labs. Had to go through a recruiter friend at one of them to get a response. Very difficult interviews but mostly feasible to prep for. Had to get somewhat lucky to get an offer, staff-level. Took about two months from beginning to prep to signing an offer. Recruiters very responsive - a little arrogant re: other companies but insecure about other labs.