I have started using @font-face for my font embedding and I have realized that TrueType fonts don’t render very smoothly in web browsers (I’ve only used them in Windows, don’t know if they are any better on a Mac) but OpenType renders fine and even Microsoft’s .EOT fonts render fine as long as they have been converted from an OpenType font. Why is this?
Thanks
No clue, what typefaces are you using? It could be something to-do with font smoothing (anti-aliasing) and how it works with stuff like Cleartype (if supported). 
I have tried many TrueType fonts, all with the same problem and im using Cleartype on my system.
You misunderstand me, I would need to know what fonts you used because some typefaces support Cleartype / font smoothing / anti-aliasing and others don’t 