Real time error reporting. Intelligent clustering and grouping of error occurrences by 10^n. Lots of flexibility in alerting rules.
Team Rollbar--I LOVE you guys and your wonderful service! This review is far too long overdue.
Let me save you a bunch of time and make the decision for you. If you're not already using an error tracking platform, you must. If you're deciding between which services to use, just go with Rollbar, and stop deliberating.
Rollbar is hands-down, THE BEST full-stack application error and exception monitoring/tracking system.
I was an early user and first started using Rollbar in early 2012 (back when it was still called Ratchet.io). Suffice it to say, it has completely transformed and leveled-up the way I build and write applications.
Rollbar is now a must-have for any application I build. TDD? Yeah, could do that, or you can just be more lean and start building, and Rollbar will catch all of your exceptions for you. Large team? Even more so that you need Rollbar, so that you can detect and fix errors before they inconvenience your users.
Here are the reasons for why I think Rollbar is great:
Rollbar has an exceptional, world-class team. Rollbar is built by engineers, for engineers. I know because I've worked with a few folks at team Rollbar, including the founder/CEO Brian Rue, who has been a mentor and advisor to me at a few startups, and some of my elite former colleagues who were hand-picked to join the Rollbar team. They are extremely talented hackers and engineers.
Rollbar scales, an is extremely reliable. We're not just talking Mickey Mouse pretend scale, but they actually do. Guess what? Unlike most of the rest of the web, they're actually NOT primarily an AWS-based stack (yeah, because AWS outages can cause large chunks of the web to fail). Rollbar is in multiple data centers across the world for improved latency, durability/reliability of data.
Rollbar is extremely easy to integrate and very well documented. There are modules/agents for just about every stack and programming language. A basic setup takes 5-10 minutes.
Rollbar is thoughtful. In the early days of Rollbar, data wasn't scrubbed so potentially you could see sensitive information in the notifications you got. Now, they've significantly improved the reporting agents and UI so that sensitive information can be scrubbed before sending notifications, and additional sensitive/PII fields can be configured in the interface.
Rollbar beats the pants off of their competitors. The primary competitors I'm thinking of are Sentry and New Relic. New Relic is more for infrastructure than application, and often, infrastructure smells and problems are code problems. In terms of budgeting or planning IT spend, I would maximize spending on Rollbar and maybe some more basic infrastructure monitoring like hand-rolled Nagios or even Datadog (which also totally rocks, btw) instead of New Relic. As for comparison with Sentry? See next bullet point.
Rollbar is an adult, whereas Sentry** is a kid. Sentry came out of Disqus, and was built by designer-engineers. Don't get me wrong--they have good engineers, but not as good as Rollbar's. I don't care if Sentry is more popular atm or if the UI looks better; I want to know that I can have absolute confidence in my error tracking platform and sleep better at night. If error tracking services were facial hair, Rollbar would be a full, lush beard, and Sentry would be the teenage kid with sporadic prickly hairs here and there and some peach fuzz on the side. Rollbar doesn't rate-limit by default, which means you get all of your exception occurrences notified and tracked. It is 4K Ultra HD, if you will. (Though, to help manage costs and temper noise, you can set custom rate limits per API key--this is so powerful!) Sentry rate-limits by default, resulting in "sampling" error tracking which isn't full coverage and leaves you erroneously thinking that your app is in better health than it actually is.
Rollbar is "multi-tenant" (similar to GitHub) in the sense that you can have one user account affiliated with multiple organizations and projects. This is a nice added convenience.
Rollbar is enterprise-ready and has on-premise deployments.
As of this review, it's 2016--why aren't you using Rollbar yet? If you're still trying to hand-roll your own error logging system, I would seriously question you or your company's technical competence.