I went through a 3 round interview and I put quite a bit of time into prepping for the technical challenge in the second round. I know I should not really expect feedback but it always is disappointing to put a ton of time into prepping for a technical challenge and get rejected without any word beyond a fairly generic rejection letter.
Also of note, the process from application took nearly 3 months. It was 1 month from applying to being asked to schedule the first round.