Well, if you mean in terms of updating, yes that was very smooth. Stuff works nice and in my case the screen is more responsive... How to put this in English? If you get a notification when your phone is locked, I usually had to tap 3-5 times on the chat-notification to unlock and open to say, Whatsapp. Now I can tap once and it opens up. Very nice!
Also, the "phone storage" got a complete overhaul, in the good way. I see sections with apps+games, music+video, pictures, documents, maps, email+messaging, system and temporary files. Especially the last one is nice to have, my phone storage went down from 13GB's used down to 10,99 GB because now I can delete temporary files
Haven't seen a way to change the default notification sound... Thats a bit of a let-down. But who knows, I haven't really dug that much in the changes. Overal my phone just feels a lot snappier again!
And I'm not sure about official release date, but wasn't that somewhere at the end of this month/start of next month?