When comparing Gitter.im vs IRC, the Slant community recommends Gitter.im for most people. In the question“What is the best team chat software?” Gitter.im is ranked 11th while IRC is ranked 12th. The most important reason people chose Gitter.im is:
Integrations for Trello, Jenkins, Travis CI, Heroku, Sentry, BitBucket, HuBoard, Logentries, Pagerduty & Sprintly are available.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Has many developer-friendly integrations
Integrations for Trello, Jenkins, Travis CI, Heroku, Sentry, BitBucket, HuBoard, Logentries, Pagerduty & Sprintly are available.
Pro Unlimited public and private rooms for free
Pro Has full Markdown support
Pro Has an IRC bridge
Pro Has apps for OSX, iOS and Chrome
Pro Has a Windows 8 app
Unofficial app for Gitter.im is currently available.
Pro Open source
Pro Open protocol
The IRC protocol is public and open, it is mature and stable, and has been implemented in numerous projects. This means that it can be used freely, for both open-source and commercial projects.
Pro Versatile
IRC offers choice. Choice in clients (mobile, desktop, web), in scripts those clients run, in servers and features those servers have. You can even set up your own server.
Pro Less distracting
Compared to other common solutions, IRC can be ignored when you are occupied doing something else. Most clients don't pester you with sounds or distracting visuals.
Pro Mentions
Every notable IRC client supports mentions - notifying you when your name is mentioned in the chat. The mentions in IRC are comparably better than Discord. Mentions used in Discord are easily abused; this doesn't happen in IRC. If someone's talking about you, you get a notification in IRC. This doesn't happen in something like Discord.
Pro Hundreds of avaliable clients
IRC has been around since 1988, so there is a ton of existing software to work with it. Everything from clients, to chat bots, to bouncers is already built.
Pro IRC networks are not centralized
You can choose your favorite server for an IRC network.
Pro No account necessary
No need to sign up for access, confirm your e-mail address. Just choose a nickname and you're done.
Pro User-friendly
IRC is user friendly if you use something like hexchat or kiwi webchat.
Pro DCC
Direct Client-to-Client allows users to share files in a similar way to torrenting.
Pro Great historic importance
Twitter hashtags came from IRC channel names.
Pro Upcoming IRCv3 will provide missing features
Cons
Con Centralized
Con Apps / UX limited in functionality and can be buggy
Con Complex and not user friendly
Con Assumes some level of prior knowledge
The features are not discoverable the way they are in other apps and services.
Con You have to "idle" to see what's going on
You will see a blank chat screen at first because there is no recent history kept on servers.
Con Can be addictive
Con Poor multimedia support
Sending anything besides text is not easy or intuitive and depends on the client.