Well, I am the proud owner of a refurb lapdock that I got for $175. (It looks brand new.) The built quality is of high quality. Its made out of metel, very thin and compact in size. (I don't own a laptop, netbook, notebook or tablet.) I've only had it a few days, but thought I'd give the answers to my questions, in case someone else was wondering the same thing.
1) I was able to purchase thru AT&T's website and kept my unlimited data plan.
2) I am able to watch movies stored in internal memory or SD card, as well as Netflix, view my pictures, check my e-mails, send SMS and edit/create word, excel, power point presentations and view PDF's. (Most of this done in the Mobil view.) I can excess the internet using the browser app, in the mobile view. This is great since now I have access to the internet no matter where I go.
I'm going out of town and will be taking this with. I will report back as to how my experience is. I will say though, the lapdock charges the phone really fast and the battery life seems on pair with the 8 hrs of use as specified.