it runs various QML programs and there are a bunch of web based things mildly optimised for it.
Yes, you can run a terminal out of the box.
No, you can't run KDE or a different GUI (well you probably can, but if you were going there this isn't a good starting place)
The scopes are equally pointless with or without privacy violating things (and really, that is almost entirely bogus FUD anyway based on the misunderstanding that the global search box in Unity was an application launcher, those concerns don't apply on the phone (there is no global multi-scope search)). Scopes are just categories of things you can search for, they are not that exciting.
It uses a browser based on QML and Webkit, it is called Oxide and they ripped off the Safari icon for it (compass needle pointing north east).
If you know Ubuntu and have been using it avidly since 2006 and know Unity 7 really well, then forget all that you have learned because this isn't the same at all. It is a new phone platform, bit like Android or iOS with no clearly defined market. I have one, it is my one and only phone, it is OK, but really I am not very demanding and completely anti-social so I don't really need to have a phone at all :)