I have come across an odd problem using 'Helvetica Neue W01 97 Black Cn' @font-face font from webfonts.fonts.com
When used in Windows based browsers (tested FF and IE), in this case in a submit button, the text seems to acquire an extra 4px or so of padding (see ff-pc-style.png). In the case of my current design, this centers it perfectly in the submit box.
In OS X, across Firefox, Safari, Chrome and Opera, the padding is lost, yet an extra 0.4px is added to the line height and height (see ff-pc-style.png).
If I remove the custom font, the fallback font (Arial), appears properly centered in OS X.
Why does this occur? And how would I get round it?
Platform detection seems like overkill just to fix a font ...
ff-pc-style.png

ff-pc-style.png
