When I got up this morning, the library files' download had completed, but the zip file was corrupt so I was unable to install them. I don't think I'll bother with a retry, given that the new instruments are not likely to be of interest to me anyway.
dub, I was able to navigate the instrument browser using only the keyboard (right-arrow to expand a category, left-arrow to collapse it, Enter or right-arrow to load an instrument), if that's what you mean. I could not figure out keypresses for paging through the browser (PgUp, PgDn do nothing), switching views, playing the virtual keyboard or adjusting any parameters.
Mesh, my motivation for buying ST3 was twofold: 1) ST2 was a favorite that no longer worked in my new 64-bit DAW, and 2) I was hoping ST3's long gestation meant either more or drastically better-sounding instruments.
I was satisfied on point 1, as it did import all my favorite ST2 libraries (I'm not sure all of them sound exactly the same, though). Point 2 was something of a disappointment, as sound quality varies from poor to mediocre to very good, and there aren't many instruments I didn't already have.
Bottom line is I spent hundreds of dollars to keep on using ST2 and Miroslav, plus picking up a handful of useful instruments. Those additions to my sound palette were enough to justify the expense, but just barely. I don't regret the purchase.