Currently on Beta and soon to be released (if it hasn't already at the time of this writing), there are some changes to make it easier to work with. It also seems to be smaller in file size for a faster boot. It also uses a new Windows Manager called "Matter" which makes layering and window stacking easier; personally I never had a problem with this. But even though the OS is a bit smaller, the "Matter" Windows Manager uses more RAM so it is recommended for R-Pies with 2GB or more. One thing I did notice in the video, the icons were "prettier and colorful than before, with folder icons with a mini icon in them. If you have a R-Pi with less then 2GB, it will use the older Windows Manager which takes up a lot less space in RAM.
 
There are more notifications, like removing a USB Thumb Drive without ejecting it, which on the past went unnoticed and the system took care of any issues that may have come up, the new OS warns you that you removed the USB Drive without ejecting it first.
 
Since this OS is in Beta, a few things that were advertised did not work so chances are they will be in the final product. One of them is changing the menu bar color, which one can do through manipulating the config file but the app that is supposed work to make this change does not work.
 
Oddly there is an option they have to download the MagPi Magazine from the Raspberry Pi Foundation Archive with a click of a mouse. Nice but worth it? That remains to be seen. Another "feature" is a "button" on the menu bar that tells you if the OS or Apps you are using has an update you can get and install. Too much Big Brother Control for me. LOL!
 
Currently the 32Bit is out for the older R-Pies, but the 64Bit is still in Beta, even with the few bugs seen. But they do have a direct plug-in for printer connection and control which seems to work and a lot easier to use from previous OS.
 
From the Raspberry Pi Reviewer "Leepspvideo":  
https://www.youtube.com/watch?v=-sFSjBjJTxA
 
SPOILER:
Also from Leepspvideo, No Raspberry Pi 5 until March 2022.