Jeffrey Zeldman writes for 24 Ways on the vast, real problem of getting embedded type to render consistently across browsers and platforms. He explains why the appearance of type in Safari looks so different — Apple appears to have implemented its own hinting engine that ignores data in embedded font files in favour of its own rendering rules — and is rather glib about the likelihood of an easy cross-browser solution:
There are ways around this ugly type ugliness, but they involve complicated scripting and sniffing — the very nightmares from which web standards and the simplicity of
@font-face were supposed to save us. I don’t know that even mighty Typekit has figured out every needed variation yet (although, working with foundries, they probably will).
Ugly rendering is the key reason services like Typekit and its ilk are still a tough sell for most projects. Unless your audience is overwhelmingly using Webkit, results like these are hard to avoid.
Update: I’ve edited the last paragraph to better convey my thoughts.