As a technical interviewer and team lead, I liked to spend the first half of the interview on technical questions and answers, and maybe some discussion on that, then the second half just having a conversation. I've rejected candidates who were technically sound, but would not be a good fit for the team (they would likely fit in somewhere, and I'd be willing to admit it was a mistake if I just read things wrong or they had a bad day). I also spend some time on who I am, what I expect, etc. This interview style doesn't seem super common, but I feel I've been pretty successful in my recommendations to the hiring manager following this, and the hiring mistakes have been pretty minimal.

I think the worst interview process I've been through is when I did 8 interviews at a company, 6 of which were technical, and then was not hired (overqualified apparently...I'm old enough to start encountering ageism and all that). Such a monumental waste of time.