I've been using it in the beta for a while. The new overlay is definitely the biggest improvement for me. Everything is snappier, and the new notes feature is nice. It initially didn't have the ability to show players in the same lobby as you like the old overlay (in games that supported it, like TF2). But they re-added it after some feedback.
Steam Update Makes Big Changes to the User Interface (gamerant.com)
They're actually really nice!
Starfield has "fewest bugs that any game from Bethesda has ever shipped with", Microsoft says (www.eurogamer.net)