It's an interesting site. Did you download as a PDF file? I didn't see any other option that involved downloading. The online reader is similar to the one on Footnote. The files are too massive to download the whole census. I checked out one portion of Philadelphia in Pennsylvania and it was over 600 meg. I think I'll experiment more with the online viewer.
BTW what did you think of the first episode of Who Do You Think You Are? Personally, I found it disappointing. Too much staging, all the work done by professional genealogists behind the scenes so SJP could jet across country and utter endless OMG's in close-ups! Sorry. I guess I'm acting a bit like Simon Cowell