Currently the main chat is happening on Telegram. People have raised some concerns/issues:
Only one owner, this is difficult to transfer and results in a single point of failure that can only be recovered if you’re able to prove to telegram you own it (like messaging them from twitter and e-mail, and instagram associated with the name/branding of the channel, yes we had to do this for leeds hackspace)
Chat log is difficult to navigate through, especially if you’ve missed messages, and you’re using only the desktop or the mobile clients.
It doesn’t really integrate with anything else, there are bots and you can dedicate a room to this integration, though other chat tools have more natural integration such as Hipchat and Slack.
Creating new rooms can end up cluttering your experience of using telegram, especially if you’re already in a number of rooms already.
Though other chat mediums also have their flaws.
IRC natively doesn’t do any form of chat logging unless you setup a bouncer, and know how to setup a bouncer, and its clients vary in usability or introduce a cost (IRCCloud).
Slack requires that you invite people to use it, though this has simple enough workarounds. It is mostly free, unless if you want to be able to access your chat history (and this can affect private messages). Though there are other workarounds for that (chat can be dumped via its API and saved if necessary) but it has easy integration with github, other bots and is generally well supported. There’s also the possibility of getting it for free for not-for-profits, though the gateway for that in the UK at least is proving you’re a charity.
Hipchat is similar to Slack, except for the API workaround as far as I know and it can be harder to invite people to it.
There’s a lot to be said for sticking with what is currently being used, chat is difficult to follow regardless, and any form of online social media can give the feeling of ‘erk I’m missing something important’ or ‘do we have to explain all of this again?’ - I think the pragmatic solution to those two problems are patience, process, documenting and accepting that managing decisions are still part of acting on things, though that might be a different topic entirely.
So if you have a preference for a different chat medium, or have a solution for binding them all, or want to gripe. Please do so.