First time trying out the Raspberry PI OS
I felt like I was using Puppy Linux. 
The First time the desktop displayed, a lot of what I was seeing, was very similar to the standard Puppy Linux desktop.
Taskbar and tray at top of desktop.
Left side:
Menu icon
Browser icon
File manager icon
Terminal icon
Middle area:
icon for any open programs
Right side:
Icon for Bluetooth
Icon for Network connection (icon changes with type connection)
Speaker icon for sound
Digital clock
All icons, on right side, have drop down option menus.
On the desktop:
A trash icon
If a external drive is connected, there will be a drive icon for it.
Click on drive icon to open file manager showing contents of drive.
So, I felt at home! 
Clicking on the menu icon brings up the normal list of menu sections with subsections.
But they do seem not as well divided up as Puppies menu.
A lot of the programs in the Raspberry PI OS are the same ones you find in Puppy Linux.
Overall, it seems like a usable OS 
