A good topic to introduce here, @kathirn – I am curiosy to know which tool you are looking at?.
There might be some distinction between one to one or group messaging chat applications (Google as you mention, as well as Signal, WhatsApp, Telegram, etc) vs what are more like the group collaboration tools the Slack/Teams/Dicord/RocketChat/etc.
In many cases an organizations platform choice is a big factor, so the MS schools will have teams available. As well in the mix are the desire to have control over the platform as you and @lightweight state the proprietary/open source are important.
To me at a general functional level what they do is not all that significantly different, yet we make it seem so when we compare.
But true that Discord’s voice channel is a special feature, we do use huddles in our Slack. Also I find important well if the tool has a means to use integration tools to connect outside services- I use various Slack add ons to add notifications and have used other tools to say use RSS feeds to post content into Discord.
Mostly we make a judgement based on what we familiar with, if you have used Slack before, going to a new one is no barrier to learn, but toss into say Zulip or RocketChat there is an amount of new learning. So people seem partial to ones they have good experiences in.
As well, to some degree (to me) the tool matters not as much as the atmosphere of those who are there, the degree to which they are facilitated, and how active they are. I think the how and what we do in spaces is more important than tools themselves.
For me, I have used the most is Slack (we use it at OEGlobal for our internal work), as it was prominent when it first came out, but I have no problem using Zulip say in the Creative Commons Community.
I have used Discord for say the Open Education Conference and with some Reclaim Hosting events and currently with MYFest. I find it a bit “blingy” amd I loathe the pitches to add things I am not asking for. I do not always like knowing they are. single source platform that has been hit by breaches.
O have had good interactions in Mattermost, it has been used well with the OpenETC to set up cpourse and project spaces for British Columbia educators, I think it is being phased out is that right @clintlalonde @ammienoot ??
I have used Matrix a few times as well RocketChat.
Again to me what/how they do is not terribly different, but there are more compelling factors for those who are dedicated to owning their platform.
Lookign forward to reading other’s thoughts and opinions.