I’ve been using Zotero since I was in grad school and at one point wrote large chunks of the BibTeX export. My first papers were added to my library in October 2006. It’s amazing to have a single source of basically every paper I’ve read in the past 16 years and many books, newspaper articles, etc - including notes. I’ve always had it backed to my own WebDav server that has, somehow, survived despite numerous migrations.

The UI is starting to feel a bit clunky, but it’s fine as a standalone application and the mobile version is great too.

Yes, it can be a tad clunky and the mobile app for a long time was just a catalog.

However, their new iOS app [1] is awesome. The ability to read and highlight right in the app is what I have been wanting for years.

I had previously been using the ZotFile [2] plugin to achieve something similar previously. ZotFile is also very powerful, I only used a subset of features.

[1] https://www.zotero.org/support/ios

[2] http://zotfile.com/

Zotero is quite possibly the LEAST WORST solution I've found.

I've tried Zotero and Mendeley during my school days. Didn't stick to any of it. But they were good.