LogSnarf is considered beta quality software. However, it is already in use in production, and may already be suitable for your needs.

Your data is secure

LogSnarf does not store any of your log data, and it stores metrics in a short-lived memory buffer to avoid overloading your time-series database with tiny requests. All requests from Heroku to LogSnarf use modern TLS Grade "A" according to SSLLabs.com".

LogSnarf needs to store credentials to your time-series database to be able to push metrics, but most databases provide "write-only" credentials which are sufficient for LogSnarf to operate. These credentials are encrypted in transit and at rest, and are never exposed after they've been added.

LogSnarf does not collect any personal data, and does not share any data with any other businesses. The only exception to this is payment processing, which is handled by a third party.

Beta caveats

• Some features are not yet complete, but are in progress. Paying customer demand may change feature prioritization, as well.
• Documentation is incomplete.

You're right, LogSnarf is relatively simple to build, a competent engineer could probably throw a proof-of-concept together in a weekend. However, if you start using those metrics for alerting, then it becomes a critical part of your infrastructure. You'll want to make sure it's reliable, with redundancies, so downtime in the service don't case false-positives or -negatives in your monitoring.

Heroku also generates a LOT of log data, only a small fraction of which contains metrics data. The log drains recieve lots of small requests that need to be handled quickly. If your service returns too many errors, or responds too slowly, Heroku will start throttling the log drain, and you'll lose data.

Even after building it, you'll need to set up monitoring and alerts, and keep on top of ongoing maintenance, which has a continual cost, both monitarily and just general effort and load on your team. In comparison, LogSnarf is extremely inexpensive.

Don't just take my word for it, Mike Perham (of Sidekiq fame) wrote about this, too.