Pinboard was nice and simple once, but nowadays doesn't seem to be maintained and is broken in many ways. I've been trying to export my archive backup for almost a year without success.
It feels more "complete" than "unmaintained" to me. It's pretty basic in what it does, but it does that well. I haven't noticed any bugs as such - what did you find that's actually broken?
I am a long-time user and archiving broke on my account at least half a year ago. Despite two support emails I did not get any replies. Feels quite "unmaintained" to me.