custom fonts with different vertical metrics between OS's

Fonts have three sets of embedded vertical metrics information. One set for Mac, one set for PC and another set typically used by *nix. These can be difficult to synchronize but our Font-face Generator does try to get these values the same. Give it a try?

http://www.fontsquirrel.com/fontface/generator

More info from the Google type team:

http://code.google.com/p/googlefontdirectory/wiki/VerticalMetricsRecommendations

I had the same problem with this font: http://www.fontsquirrel.com/fonts/Symbol-Signs

I downloaded the prepackaged @font-face kit and the metrics were inconsistent between Mac and PC.

The solution was to take the TTF font out of the downloaded kit and use it to export a new @font-face kit with Font Squirrel's generator. The generator has a checkbox in the Expert Settings labeled "Fix Vertical Metrics". Make sure this is checked before you generate your kit.