It's already got lots of plugins, but it's fairly easy to add your own as well. It's in the mature / complete category of projects in my opinion (although there's still some development happening)
Agreed.
After writing my own static site generator in Python, I went back and was impressed with all the options available in Pelican. Lots of things I wished I had built were included.
I'm using my own hacked-together very basic system in Python right now, and am pretty happy with it. No doubt I might find myself wanting more features soon, but here's hoping I can stick with it, it's the first moderately interesting side project I've worked on.
It's already got lots of plugins, but it's fairly easy to add your own as well. It's in the mature / complete category of projects in my opinion (although there's still some development happening)