What's a final interview like?

Like an interview, but more final.

Honestly I haven’t noticed much difference in them, you just get the same sort of interview but with someone higher up.

Curious to hear some employers point of view as well.

It can be very different depending on the company. If the first interview is more general, the final interview could be a lot more specific concerning the actual job role and depending on the role, could be a very technical interview. In my experiences, the final interview is much like the initial with higher-ups.