@93terp: 1 font set at a time, yes. (That means 1 Serif / 1 Sans / 1 Mono). There's a link on the wiki to a page with K2 screenshots. For the K3, that'll look mostly like in the Windows (or Linux with BCI, but *not* OS X) Font Previewer, but, as always, it pays to see it for yourself, screenshots aren't very accurate in this case.
@all: Posted a bunch of K3 packages for a few of the fonts in the second or third post, they should look a bit better than the previous ones
. I didn't test everything, so if some of the styles look weird (Most likely the Bolds or Fontin Sans), mix them with the one from the previous packages, they'll be a bit fuzzier, but that may look better in the end).
@daffy4u: Didn't try the old Fontin packages, but the latest (K3) works fine here.