When I said greyscale rendering, that implied greyscale *anti aliasing* too
So, obviously no SPR (ie. ClearType) on the Kindle
(FT can do SPR, but it's not enabled by defaut, again because of patents. And the 5-way FIR filter applied to smooth color fringes is entirely configurable. But SPR wouldn't make sense on a e-Ink display in our case anyway).
As for hinting, there's three different hinting levels. The actual difference they do to the output is pretty easily seen with the utils bundled with FT. But like I said, not sure exactly what level is used on the Kindle.
Regarding TrueType instructions, I'm pretty sure the Kindle doesn't use them (FT can, via the bytecode interpreter, but since it was still covered by patents, it wasn't enabled by default 'til very recently).
Long story short: FT is very powerful, and, very, very configurable
. But in the Kindle case, we more or less know what the settings used are, so that helps
EDIT: Take a look at that screenshot (with the FT util ftdiff). I'm pretty sure what's used on the Kindle is more or less the settings of the 3rd or 2nd column in my example, since I'm pretty sure it doesn't use FT's native bytecode interpreter. The text in the browser (Chromium) is rendered by FT, with full hinting, the auto-hinter, and RGB SPR with the 5-way FIR filter using the gibson coefficient as weight. (Which is a pretty heavily customized setup compared to most default Linux distro... ^^)