Here is a screenshot of some text from the Google Play store rendered in IE, Firefox and Chrome. Click the image to see it in its full size:
Firefox looks the best to me; Chrome the worst. IE is not great either, but it is better at larger font sizes than Chrome (IMO).
You might argue that the difference in each browser is not great, but it is a noticeable difference.
I would have thought that text rendering would be top priority from a UX perspective given that reading text constitutes such a major part of browsing the web.