Here are some screenshots from Firefox for Windows:
I've switched back to Arial and got this GIF animation:
Here's a screenshot from Chrome for Windows: it looks quite different.
Browsers like Firefox and Chrome show a lot of information about fonts: you can select some text, right-click, pick "inspect element", switch to the Fonts or Computed tab and find the fonts that are used.
9to5Google.com says that "the font comes in several weights, but the one Google has gone with is slightly lighter than what users may be used to compared to the Arial font. This will surely lead to some complaints about it being harder to read".