Not as important as other issues mentioned above, the material editor seems to load a lot longer, also on first load-up it kinda hangs itself and max for 3-7sec as if it's buffering or loading all it's previews into ram/cache?
If material editor is closed and reopened it does the hanging thing again, otherwise while it is opened it works fine. Also some thumbs are kinda shifted or off the grid.
P.S. machine with loads of ram, good GPU and CPU - so that is not the issue for long load times.