Jason Campbell : I hope this answers your question on the validity of using one rasterer to find problems with the another.
As part of the effort leading up to Font Validator 2.0, I
tested all the fonts I have in my processsion on both 2.0 and 1.0, at
just size 10, for B/W rendering (the full run is about 70 sizes from 4
to 126, and B/W + gray + subpixel rendering, and obviously will take
about 200x as long) . That's ~2000 fonts on Fedora, ~700 for Mac OS X,
~2000 mostly old and rather buggy CJK fonts of my private collection,
and I have always been comparing the results for the ~300 fonts shipped
with windows 8.1. So that's about 5000 fonts used for testing. And I
posted the URL for the libre font part.
I reckon nobody is going
to download a file to see if his/her font is listed in the flaws
found... So let's simply name the fonts - it is divided into 1.0 (the
older binary only Font Validator) and 2.0, and texlive vs non-texlive.
Of course the hope is that some of the flaws will get fixed.
think for most part Font Validator 2.0 tries to be less buggy, so if
your font is in the 1.0 list but not in the 2.0 list (or a flaw appears
in the 1.0 list but not 2.0), and you cannot figure out why 1.0
complains, it probably is just 1.0 being buggy; but I'd certainly like
to hear otherwise, or that 2.0 did not detect a genuine flaw.
The actual details, i.e. which glyph at what offset has what kind of problems, are up at:http://htl10.users.sourceforge.net/tmp/FontVal-test-results-2016July/
dotnet/mono binary (-bin.zip) and mac os binary (dmg) up at , and please do make a donation  if you find this useful.