The interview process is quite long. There was a written interview, which was very detailed and took some time to complete, but you have a month to do so. Next there is a psychometric test (The Thomas Assessment), which was pretty easy and fast and requires no preparation and you get your results back pretty fast. Personally, I scored the top grade in all areas of the test, so I was feeling pretty confident that even if I was not considered for this role, they would divert my application to another role they thought to be more suitable. There was over a month of time between when the pyschometric test opened up and when they opened up the technical assessment, and there was no communication during this time. There was about a week to complete the technical assessment, which required coding in your chosen language to address a prompt. Not all positions will have this element, and I wasn't even sure if mine would until it was released, since it was not on the candidate portal. Within a couple days of the technical assessment due date, I was notified I would not be moving forward to interviews. No reasoning was provided due to a high volume of candidates. If I had moved on, there would've been several rounds of interviews before a final decision would be made.
I appreciate that Canonical wants to get to know you in depth and test your strengths in multiple areas. Depending on who from the company is assigned to lead the hiring process for your position, they may be more or less responsive. However, the application process is extremely time consuming from the very beginning. If you are looking for an urgent job placement, know it may be many MANY months before you are potentially hired. I would only recommend applying here if you don't need a position urgently and have PLENTY of time on your hands to complete the process.
I personally feel the time Canonical expects from you upfront is inconsiderate to candidates. As each part of the process is completed and time goes on between each step, candidates will inevitably develop an emotional investment to the position as they invest so much of their time. This attachment is likely to grow even though realistically, most applications will be tossed to the wayside. Due to the high volume of candidates, the hiring manager cannot provide feedback on why you were dropped from the process and they do not divert you to another more suitable roles as they mislead you to think is likely.
All in all, if canonical wants to attract the best candidates and treat them with respect and consideration, they need to cut down on the amount of time it takes upfront. It is too much of an investment that is so unlikely to get a return.