It's still beta though, just add "-clientbeta betaui" to your shortcut and see the magic 
It looks infinitly better, has more options to customise and works a bit better. (like being able to hide games you don't have installed!!! - bit annoying when you have the entire VALVe backlog and only want to play Source engine games.
It's only the front end, the UI in the game itself is exactly the same. It seems to start up faster as well, but no way to check that for certain. As of now no errors or weird things, so it seems pretty stable as well. Downgrading is easy, just remove the comment again and you're good to go!
It looks infinitly better, has more options to customise and works a bit better. (like being able to hide games you don't have installed!!! - bit annoying when you have the entire VALVe backlog and only want to play Source engine games.
It's only the front end, the UI in the game itself is exactly the same. It seems to start up faster as well, but no way to check that for certain. As of now no errors or weird things, so it seems pretty stable as well. Downgrading is easy, just remove the comment again and you're good to go!