Windows font rasterization techniques make small fonts appear sharp, but at the same time heavily distorts characters and letter spacing by using imprecise and strong hinting.
(For pictures and detailed description please refer to this article:
That's why in some cases printed documents appear slightly different from what's seen on-screen.
An option should be added to the 'Adjust clear type' window to turn font hinting on and off. (or even make a slider to adjust hinting strength as found in some linux distribs)
This would basically make text appear similar to MacOS style (slightly bolder and blurrer for small fonts, but there will be no distorted chars nor weird spacing).
Also would be useful to implement the feature at per-application basis. (for example, it may be helpful for precisely positioning text in Word, but useless in notepad and console apps).
You can use the GDI++ utility to get rid of hinting in some applications (works for opera browser, chrome)