I like that it's open-source and has good community support. It's easy to get started with, has decent documentation, and integrates well with other tools (e.g., Sentry). AppSignal does not yet have an open-collector implementation, which would allow us to directly push data from our application to a Graphite endpoint. This makes it difficult to build out dashboards and integrate with 3rd party software. We use AppSignal primarily as a crash reporting tool. With AppSignal we can easily send stack traces back to our Sentry account and send notifications via Slack or email when we receive them. We're also using it to aggregate app performance metrics.