I've finally got round to trying the new IDE, here are my comments for now.
The vertical lines linking, for example, where a for loop starts and ends, are a BIG improvement. Not being able to easily follow where something started and ended is something I hate on the old IDE.
Serial monitor being at the bottom of the main window instead of being in a window of its own is horrible. If there's a way to undock it please tell me, I can't find it.
Bottom right is NOTIFICATIONS, these cover up whatever else is open at the bottom and there does not seem to be a way to get rid of them, they are just there, on top, in the way.
Most important of all the UPLOAD button does not upload. I see someone else is having the same problem Upload does nothing. So to be clear, I have a Nano Every connected, it shows up in the port list, opening the serial monitor confirms it is connected but clicking the UPLOAD button does nothing. It does not compile, it does not upload.
I can't believe this bug has always been there, it would have been noticed by now, so I assume I might be doing something wrong.