We've used MS Teams extensively at my previous employer and while I was more of an advocate for MST, we did face major stability and performance issues regularly.
I understand the choice of Electron to accelerate development, but the platform seems to be inadequate for companies with many teams and intense chatter. For me, the app would take up to a second just to switch tabs and it would occasionally feel very sluggish, all the while eating 5 % or more CPU even when idle (Surface Pro 2015). Mac users would complain about frequent needs to restart the app, which would sometimes take minutes on end.
I'm now in a position to possibly introduce Teams into a new company and I'm hesitant. It's not bad by any means, it fits nicely into our ecosystem; it's just that I'm worried about the devs' reaction to the desktop app.
Is there any chance we'll see a "proper" UWP/PWA incarnation of Teams? Slack has one and it's pretty snappy, even if it's just another container. The desktop app is currently the biggest drawback with Teams.
I'm really hoping that MS will announce a big UI/UX overhaul of Teams by 2020 that addresses a lot of the performance and navigation issues this forum (and uservoice) keep asking about. If Teams felt just a little more polished throughout the app, it would be much easier to get new users excited about it.
Ditto to this and what others have replied with. Performance is no good. Can't do the things you'd expect like resizing columns and the like. Was hoping for a better experience than Slack. Software development is getting so abstracted, no one seems to want to take advantage of hardware anymore and write performant, buttery smooth apps.