Hmmm that's not great. It looks fine for me in Firefox/Chrome on Mac. The base font is a Google webfont though (Merriweather) and sometimes I see those have random rendering problems for whatever reason.
I use palemoon. They are right now extremely upset that Google fonts is buggy, doesn't comply to standards, and Google not only refuses to fix it, but keep making changes that break palemoon workarounds. the project lead has seemly in the past months working more to create google font workarounds than on the rest of the browser.
This doesn't really surprise me. I should really download the ttf's and such and font-face it myself. My blog is built on a Jekyll theme that I lightly modified and as I recall didn't mess with the fonts at all.