We received a lot of valuable feedback on our first release of eris and recently released v0.2.0 with improvements (changelog: https://github.com/rotisserie/eris/blob/master/CHANGELOG.md).

  * Improved the stack trace for both local and global errors
  * Streamlined error formatting (it's now a single call: ToString or ToJSON)
  * Completely rewrote our documentation and added direct comparisons to pkg/errors
  * Added more examples (https://godoc.org/github.com/rotisserie/eris#pkg-examples)
  * Added Sentry support
  * Bug fixes

At this point, we're looking for more users and feedback so we can continue improving it!