Don't waste your time. Yes, they tell you they take a while to interview, but my interview was four rounds over four months, which is just ridiculous. The first two rounds were each a phone call with one person. Simple, straightforward questions. One or two math questions (If a $100 investment lost 50% last year, how much does it need to return this year to get back to $100? 100%, duh). The third round was a video interview with one person. No math, just straightforward resume, give examples of a time when you... The fourth round was the same, but was three interviews with three different people. After each round, it took a month to hear back and schedule the next one.
I didn't get selected for the job, which is fine, I get it. But at no point in any interview did I feel unqualified. I have a Masters degree and this was an entry-level job. They hardly asked any difficult questions. After the fourth round, I was asked to submit a bunch of documents (scan my diplomas, send transcripts, sign off on a background check, etc), so I thought I was going to get an offer, and didn't. Not only that, but they said they went with somebody else (again, that WOULD BE find), but then the job was reposted, so I think they just didn't like me. If that's the case, why did they waste my time for four months? That's what bothers me.
Overall, it was a bad experience. If you want to take your time, fine, but eventually it's ridiculous. And if you feel someone is unqualified, don't waste their time with four rounds of interviews. The interviewers were nice enough, but like I said, the questions were easy, so I don't know what disqualified me.