Good article, reflects my experience hiring at a small services firm, too.

One thing I'd add re: "non-obviousness." There are also tarpits; people who make you think "I can't believe my luck! How has the market missed someone this good!?" At this point, I have enough scar tissue that I immediately doubt my first instinct here. If someone is amazing on paper/in interviews and they aren't working somewhere more prestigious than my corner of the industry, there is often some mitigating factor: an abrasive personality, an uncanny ability to talk technically about systems they can't actually implement, a tendency to disappear from time to time. For these candidates, I try to focus the rest of the interview process on clearing all possible risks and identifying any mitigating factors we may have missed while getting the candidate excited to work with us assuming everything comes back clean.