I use Sentry for a fairly large Rails development project and it’s nice for tracking issues, assigning people to tasks, tracking resolution, getting alerts and integrating (in our case) with a private GitHub repo.
Because Sentry works well for this current Rails development project, I think soon we will try out this Discourse Sentry plugin and see if there is any benefits but so far it’s nice to track errors remotely and get alerts, manage assignment and tracking issue resolution.