I never used it on Linux so I can't speak to that but it's pretty bad on Windows. It wasn't great a couple years ago (on Windows) and it's only gotten worse. The downward slope of the product quality seems to be steeper each year as well. It's really frustrating to witness since they could have put out something great.

They were already sunsetting Skype, MSN Messenger was basically gone (or was it previously rolled into Skype? I can't remember). They could have started from scratch and built a really great communication tool using all of the knowledge they gained running the aforementioned products and not carrying forward all of the tech debt and glue they had to add to make the older services work with modern architecture. But they didn't and now the majority of the corporate world suffers relentless little pain points while using the software.

Not to mention it's poor quality has splash damage: loss of productivity due to issues and performance, increased IT tickets, increased computer specs to run the new features MS thinks we all need despite people not asking for. All of that amounts to millions (billions?) of dollars more spent each year for products that are themselves subpar. That cost is only growing as well.