My observations (confirming some issues others reported):
Update process: Xperia 10 ii: perfect, no issues
Xperia10 iii, stuck at 100%, forced reboot, no issues since
Xperia 10 iii: mobile hotspot doesn’t work with Vodafone SIM anymore. With SFOS 4.4 I only had problems with Congstar SIM while Vodafone (Germany) worked. Xperia 10 ii had no such issues but I haven’t tested hotspot with SFOS 4.5 on the Xperia 10 ii yet
MicroG: compromised, no fake store anymore etc. (see above) EDIT: solution: MicroG / Fake Store on SFOS 4.5 - #8 by vige
Chum: no Chum GUI anymore (see above)
All in all, SFOS feels good, though. Thank you, Sailors!!!