Testing 25.10 RC on Toshiba Sattelite laptop:
Pre install screen
pre-install screen crashed out with a "we don't know what happened, see the log" error.
Logwindow stayed completely blank so I closed the window and started the installer.
I refrained to connect to internet to avoid any potential problems and chose a minimal install.
installing:
OMG!! It installed fast !! (25 minutes)
That is a lot faster than installing 24.04 did on this same laptop (which took hours).
25 minuts may seem slow but keep in mind that this old beast is still running on a classical harddisk and is pretty slow (and partly damaged) to begin with.
When invoking the installer, it immediately popped up an error which I answered with 'report' (good luck without an internet connection). It continued without complaints nevertheless.
The installer had no flickering window and no glitches, pretty amazing !
Firefox:
no problem whatsoever, snappy as could be 
Appcenter
No problem whatsoever, works flawlessly on this old craptop. 
Quite a progress since 24.04, I didn't expect that. Amazing. 
Localization
Failed to localize directory names ofcourse, because I had no internet connection during install.
An update of both the system and the languagepacks did not change that.
However, creating a new user did in fact create localized directory names.
This is a quite a leap forward since 24.04
All in all, this was a much better experience than expected and much better than the 24.04 install. 