Recs.
Updated
Specs
Pros
Pro Easy integration with other applications
Airbrake integrates easily with Github, Hipchat, Asana and a number of other services, which can be viewed here. Also if you've got a custom app you'd like to integrate into Airbrake, you can use Airbrake's public API or there web hooks functionality to your advantage.
Pro Airbrake errors can be self-hosted on Errbit
Errbit is a self-hosted error catcher for Airbrake. It allows keeping errors off Airbrake's servers by using Airbrake's error tracking tools to send error logs to your own ErrBit based web service. Useful for when errors contain sensitive client data.
Pro Asynchronous error tracking script
By including Airbrake's client side error tracking JS into your code, you won't have to worry about it affecting your page load times at all. Since the library loads asynchronously, which means it won't cause painful delays for your site's visitors.