tldr; After hours of interviews and exercises they ghost and give no feedback. I managed to complete Canonical's "early stage" interviews - 4 one hour interviews and 4 exercises (1 written, 2 psychometric, and a coding exercise). Although I had great conversations and loved meeting everyone (best part), Canonical ghosted for 2 weeks despite reaching out to my hiring manager for any updates. When they did respond, it was the most generic email: "We are writing to let you know that we have reviewed your application. We regret to inform you that we shall not be progressing your application further for this particular role". Given the progress through the process I would've expected some correspondence or feedback, but they just send an inpersonal email. If they provided ANY kind of feedback that would definitely get rid of the question marks. Instead, Canonical conveys that they do not care about you or the time you spent in their overly long process, even if you do make it to the further rounds.

Awful. After submitting my CV, I was invited to take a written interview. At this point, all seemed good, there was a person assigned who could provide any information needed and when it came to completing the interview, there was no pressure to complete it in an unreasonable time frame. The interview was 50 questions. Not multiple choice, each one requiring a written answer. So, if you allow 5 minutes for each, that's over 4 hours of effort. But of course you probably spend more to make sure you're answering clearly and succinctly. After submitting, it didn't take long for a rejection to come, but despite all the time spent, they would not provide any feedback which I thought was pretty poor. They did however have the nerve to ask for feedback on their process.