The title / post-meta styling is an improvement, I agree. As for the body test—what OS / browser / etc. is that?
Edit: I ask because, from what I've seen, Fira Sans is more readable on more platform/browser/device combinations than Concourse, as a body text font. In this case it's closer to the opposite… let me ask you this: how much of the difference between the two versions you screenshotted, for you, is made by the body text size, as distinct from the typeface per se?
Yeah, it's probably about font size.
The screenshots were taken on Ubuntu + Chrome. I came home and checked on my Mac, and it seems like Fira isn't always that bad. Ubuntu just stretches it for some reason and it looks horrible, like in my "Before" screenshot. As for Concourse, I managed to make it look like my "After" screenshot on both platforms by setting -webkit-font-smoothing: antialiased. But that seems brittle. So yeah, fonts are tricky and I withdraw my proposal, at least until I get ten different machines to test it :-)
Might as well go with a bang.