I was really optimistic about this tool, but I feel like the app is stagnating. What killed it for me was that since 1.4 you can't switch to other organizations any more where you are registered as a guest - since April Teams 1.4 immediately switches back to your main O365 organization. As a consultant who works with different organizations that have added me to their teams as a guest, that makes the app unusable for me, as it's pointless if I can't work with my clients.
What is frustrating is that Microsoft has acknowledged the problem and has since then pushed an update, but the problem is still around. There is no transparency and no roadmap. A for effort, though, I appreciate that MS has at least been trying.
Instead of the app I now use the dev version of Microsoft Edge for Linux and use the Teams web client in Edge. It is in fact more functional than the standalone version, with support to everything that the standalone client supports, plus more than 4 video feeds and Together Mode.