AppSignal is very easy to add to your Ruby on Rails applications and out-of-the-box it provides many meaningful metrics both for web requests as well as background jobs. Later we also added several custom events specific to our application and it was quite easy. We also like that it supports JRuby which we use (as some monitoring tools only support MRI implementation of Ruby). Previously we used New Relic and comparing to that AppSignal was easier to use as well as the AppSignal pricing model is much better compared to New Relic.

Fair pricing, kind pricing policies, good developer experience. I use it for monitoring an Elixir and React application as well as for a Rails project. It just works, without having to jump through any hoops.

Fair pricing models, complete set of tools to diagnose, get insights and act on performance pain points and error logging. It's a must in my projects.