This is a story for people who have been grieving, people who had to see their loved ones grow old and die, people who feel the passage of time around them and who noticed too late that they maybe didn't know all there was to know about their loved ones.
If any of this applies to you, you will rarely see an anime that understands those feelings as well as Sousou no Frieren.
While the main plot seems heavy in theory, it is rather lighthearted in execution. We get to see the main character make new friends and connections just as much as we see her thinking about the past. There is even the occasional, well-timed, comic-relief.
Whiile the series is slow, it did not get boring. The deeper themes keep it interesting so far.
Art and Animation, Soundtrack and Characters are all very good.