Mononoke is a very interesting case for Japanese anime. It uses a very unique art style which I enjoy quite much. And psychological elements which I am abig fan of.
However I have..many..MANY issues with it. Maybe it's because I'm not the target demographic as I don't understand Japanese folklore, but I do understand some Yo-Kai, so maybe take my review with a grain of salt. Mononoke seems to drag on a lot, dragged on a bit too much for me that I was wondering when it was gonna be over. But when it gets going you can see actual storytelling and deeper meanings. However it's inconsistencies outweigh it for me. It just went from being very confusing and it slowly fed you details over time, but I really didn't like the way they did it.
The concept of the truth and regret with the Medicine Seller's sword though is very clever on their part and they did a very good job to it.
Overall, despite very confusing I still somewhat enjoyed it and would recommend giving it a try if you want something different from anime.