No, they don't. They looked horrible in Chrome for a long time because Chrome's rendering was screwed up unless you gave it fonts in a very specific order so it used SVG. Fun fact, Google Web Fonts never served it in that very specific order.
Try disabling Direct Write. Chrome 37 pushed a fix for the font aliasing problem that resolved it for most users but made it worse for a few. See this ticket for details: https://code.google.com/p/chromium/issues/detail?id=444141 (sucks that this is still an issue so many years later)
That's not Chrome, it's Firefox. Looks the same on my machine as well, all jaggedy. I'm using FF 36. Let me go update and see if there's a difference...
It's likely an issue with buggy video drivers. Firefox has a database of drivers on a blacklist that will crash due to instability. When it detects them in use, it will disable hardware acceleration which decreases performance and quality of some things like font rendering. Judging by the earlier screenshot, this is on a lower end laptop at 1366x768 resolution with an integrated graphics card. Most laptop makers never update the bundled drivers to fix bugs even though Intel and AMD regularly update the drivers of their integrated graphics tech. So, users are stuck with an outdated buggy driver and no way to update it. Mozilla at least ensures that it won't crash.
My screenshot is from a PC with AMD A10-7850K with integrated Radeon R7 graphics. I always download the latest AMD drivers and check for updates every month.
Judging by the jagginess and the low resolution of your screen, I'd wager you're using one of the laptops with an integrated GPU that's using an older version of the drivers that's on the Firefox GPU blacklist. This is usually because the laptop maker doesn't bother to update the graphics drivers much, if at all, and doesn't get the improved ones from Intel/AMD/etc. These outdated and buggy graphics drivers cause apps that use hardware acceleration to crash, so Firefox is running with it off on your laptop. Mozilla maintains a blacklist of known bad versions of graphics drivers and will automatically disable hardware acceleration on those machines so that it won't crash. With it off, web pages won't look as good and web fonts won't be as smooth.
Neither my laptop nor my desktop suffer this issue with Firefox, Chrome, IE, etc.
Windows and OS X use different methods of hinting where Windows attempts to stay true to the typeface and OS X attempts to provide a provide a smoother, more readable version. Webkit browsers give you some level of control with subpixel rendering CSS attributes, but fonts might still look awful in Firefox or IE on Windows.
Also Windows 8 uses subpixel positioned grayscale, rather than subpixel positioned ClearType.
When you rotate a tablet by 90degrees ClearType doesn't work.
