Guest Fedora 29 kde but still on kernel 4.18.18. Guest additions installed.
Intel i7-6700
16 gb memory on machine. 4gb for the client.
Turned this on for an existing VM. Not a new VM install. One issue is the screen size is small (svga?) after a reboot ... though if I shutdown first it's ok upon start again. I can resize the window but it is again lost with a reboot.
Another issue is when I make a snapshot it appears as corrupted in the "Preview" pain and upon restore it ends up as a black screen until I shut it down after about 15 seconds or so.
Maybe it's really meant for new VM installs ?? ... but there is nothing in the manual that says that.
I'm sure a little more spit and polish will make this a better choice
Things are looking up for VBox.
JC