Great , powerful for those who want to do all of their work in only markdown. If you're a coder and already use a text editor day and day out , you could do a lot in those tools too and might not need to invest in the learning curve here.
Obsidian is by far the most valuable product I interact with on a day-to-day. I've been using it since the beginning and the evolution of the community and product is so beautiful. Obsidian is quite literately my second brain until I die.