Whether TKey or Precursor is better depends on your needs. Here are some differences between them:

* TKey uses open tooling for everything. Precursor uses Vivado.

* Precursor has a screen and a keyboard, allowing the user to interact directly with the trusted device in a completely different way than the TKey.

* The Precursor is bigger than the TKey.

* The Precursor costs much more than the TKey.

Finally I'd just like to mentiont that bunnie and xobs work on Precursor as well as their other projects have been a great inspiration to the TKey project.

I'm not affiliated with either but I just looked at the precursor page because I'm a huge nerd and love crowdfunded projects.

They seem to be in slightly different leagues. Tkey is small and meant to be easily carried with you to authenticate with ssh, gpg and more. While precursor is a full development board that can probably do everything tkey can, and more.

Different product at a different price point with different objectives. Security keys are suitable for mass deployment across an entire workforce, precursor aims to be a launchboard for general purpose secure and trustable computation. Even at mass production prices, precursor would likely still cost more than 100$.