So far my testing shows this isn’t ready for production. I spent 3 hours converting my project from 5.3 to work at all on 5.4. I haven’t had this much trouble switching engine versions is years.
While the editor is running right it is resetting the GDI, and Windows 10 Pro is restarting the desktop with Lumen enabled or disabled.
Once I got it running even the content browser won’t stay where I put it after launching the editor even after saving my layout.
I am sure it is riddled with bugs but they Epic always do a good job of patching it, I expect a few point releases which is the pattern.
I am still testing performance, just from gut feel the built project seems faster, but I also disabled Lumen and all those rendering features to get the performance of 4.27.2 back. Now I am testing Lumen.
Update 1: Lumen still performs poorly - disable it if you want FPS use the old methods. Also you will want to really convert your project to using Enhanced Input if you are still using the older input method it seems to throw a lot of errors even disabling Enhanced Input at the project level still causes console errors but it works.