Received my AT&T Unite hotspot unit today and am happy to confirm that it works beautifully with my iPad Mini's unlimited data sim. Using it was as simple as removing the nano sim from my Nexus 7, placing it into a full size sim adapter and inserting it into the Unite--no setup or configuration required. I connected with a couple of different devices and saw DL speeds around 30 Mbps over LTE.
How come nobody told me that once you insert a sim card with an adapter in the unite it will never get out unless you force it. I've already broke two unite hotspots because the sim+adapter won't get out. they get stuck with the sim contacts and the only way to get it , has anybody success taking the sim out with out damaging the contacts?