The process was not difficult, just very negative. Going into a six hour interview, with no breaks for use of facilities or to have a snack just to keep a hunger noises down during the process, appears inconsiderate on their part. Additionally, having interviewers swear and/or ask illegal questions during the interview is highly unprofessional - which happened. It was quite possibly the worst interview experience I've had in my 25 years of working, and quite disappointing.
I was asked four times for my pay requirements - which is excessive since it was provided three times prior to this long day -- that's seven times. I was told by each interviewer throughout the process that they do not pay the industry standards, and each used the sales pitch of the quarterly bonuses that make up for the lack of pay. By the way, their pay range changed for the role from initial discussions- decreasing significantly (by $20k) from my requirements that were stated quite clearly before scheduling an all day, in person interview. On a side note, I was requiring the midrange of industry standards for the area, so not extensive.
There were not many interview questions in the six hours, it felt more like a sales pitch from beginning to end with a few illegal and non-job related questions sprinkled in. Overall, it was a disappointing experience and not a journey I'm interested in going through again.