I used the new GUI unattended install to install xubuntu kinetic. I noticed two differences from the normal Ubuntu interactive install:
The created user wasn't put in the sudo group; this is a pain on ubuntu since it doesn't have a root password, so it has to be fixed by booting the live CD and mounting the install disk.
The apt source was set to gb.archive.ubuntu.com even though I'm in the US. This is less of a pain (I probably wouldn't have noticed except it triggered a bug in one of my setup scripts.)
I didn't use a script, I used the GUI. I think this is new in 7.0, at least I've never seen it before. I didn't see any place to specify time zone, the installed OS ended up in Americas/Los_Angeles (which is where I am.)
I found not putting the user in the sudo group surprising because the unattended install GUI looks a lot like the Ubuntu installer prompts so I expected it to do pretty much the same thing.
The New VM wizard in the GUI provides a lot more functionality than in 6.1 (essentially it is all new), and defaults to attempting an unattended install if one selects an ISO straight away and the unattended install feature detects it can handle the OS on it.
The unattended install already existed in 6.1, but was available through VBoxManage CLI only.