Chrome/WebKit and Firefox have different rendering engines which render fonts differently, in particular with differing dimensions. This isn't too surprising, but what's surprising is the magnitude of some of the differences.

I can always tweak individual elements on a page to be more similar, but that's tedious, to say the least. I've been searching for more systematic solutions, but many resources (e.g. SO answers) simply say "use a reset package." While I'm sure this fixes a bunch of other things like padding and spacing, it doesn't seem to make any difference for font dimensions.

For instance, if I take the reset package from http://html5reset.org/, I can show pretty big differences (note the layout dimensions shown in the inspectors). [The images below are actually higher res than shown/resized in this answer.]

<h1 style="font-size:64px; background-color: #eee;">Article Header</h1>

With Helvetica, Chrome is has the shorter height instead.

<h1 style="font-size:64px; background-color: #eee; font-family: Helvetica">Article Header</h1>

Using a different font, Chrome again renders a much taller font, but additionally the letter spacing goes haywire (probably due to the boldification of the font):

<style>

@font-face {
  font-family: "MyriadProRegular";
  src: url("fonts/myriadpro-regular-webfont.eot");
  src: local("?"), url("fonts/myriadpro-regular-webfont.woff") format("woff"), url("fonts/myriadpro-regular-webfont.ttf") format("truetype"), url("fonts/myriadpro-regular-webfont.svg#webfonteknRmz0m") format("svg");
  font-weight: normal;
  font-style: normal; }

@font-face {
  font-family: "MyriadProLight";
  src: url("fonts/myriadpro-light-webfont.eot");
  src: local("?"), url("fonts/myriadpro-light-webfont.woff") format("woff"), url("fonts/myriadpro-light-webfont.ttf") format("truetype"), url("fonts/myriadpro-light-webfont.svg#webfont2SBUkD9p") format("svg");
  font-weight: normal;
  font-style: normal; }

@font-face {
  font-family: "MyriadProSemibold";
  src: url("fonts/myriadpro-semibold-webfont.eot");
  src: local("?"), url("fonts/myriadpro-semibold-webfont.woff") format("woff"), url("fonts/myriadpro-semibold-webfont.ttf") format("truetype"), url("fonts/myriadpro-semibold-webfont.svg#webfontM3ufnW4Z") format("svg");
  font-weight: normal;
  font-style: normal; }

</style>

...

<h1 style="font-size:64px; background-color: #eee; font-family: Helvetica">Article Header</h1>

I've tried a few resets/normalize packages to no avail. I just wanted to confirm here that this is indeed a fact of life (even omitting the more glaring offenders like IE and mobile) and I'm not missing some super-awesome solution to this mess.