I wouldn't say it works well. On some machines it takes ages to start up and will always say it's updating even though it isn't. The ingame browser that is used to view the store breaks often and thenI can't open it inside Steam at all. On Macos, the system menu completely stops working most of the time and I can't exit the app normally, I have to kill it instead.
OK, the core functionality of downloading and running games works. But I think we can expect a little bit more from a billion dollar company.