I've been forced to use it because it's the only "allowed" one for a project I'm on (since the other party has the "we already have teams for free" syndrome). It's horrible to work with, sound fails to function half of the time and it is "incompatible" with firefox (our main browser of choice).

I tried using the linux client but it simply will not allow me to connect to anyone and keeps telling me I need to login and enable teams on my "account" (we do not have a microsoft company account).