uBlock vs. uBlock Origin: what's the difference?

Citing frustration with the increasing volume of support and feature requests from users of uBlock, gorhill (the original developer behind uBlock) transferred ownership of the project to the current uBlock development team, composed of contributors to the original project.

Chris Aljoudi is now the lead developer of uBlock. Alex Vallat heads Firefox development, bringing uBlock to hundreds of thousands of Mozilla fans.

After transferring ownership of the uBlock project, gorhill forked uBlock into uBlock Origin, a personal fork for which he's been releasing builds and providing support via the extension's Chrome Web Store entry.

After the transfer, there were some issues regarding wording and attribution. After consulting with gorhill, this was promptly addressed and resolved — gorhill and the team are content and satisfied with the resolution.

Even though there were no malicious intents or actual conflicts within the team, various aggressive false rumors and accusations were being spread. Some of those are:

• gorhill was forced to give up uBlock for legal reasons.
• uBlock was "bought" from gorhill.
• uBlock is attempting to monetize.
• uBlock is an illegitimate "clone" of uBlock Origin.

... and various others. The accusations have no basis in truth, and probably rather the result of some form of the "telephone"/Chinese whispers game.

It's been openly discussed and offered to transfer uBlock back to gorhill; he has declined the offer.

Which one am I using? Should I switch to the other one?

You can tell by looking at the uBlock icon:

You're welcome and should feel free to use either per your own judgment. If you're currently using uBlock Origin, you're welcome to move over to the main uBlock project.

Please note that the uBlock development team only supports uBlock, not uBlock Origin. Thus, uBlock Origin-specific issues are under gorhill's control.