I read HN on my Kindle's browser fairly regularly. HN itself (and similar pages with a simple layout, such as i.reddit.com) works great. For the articles that are linked, it's a coin flip whether it works or the page has so much cruft that it crashes the browser.

I used to use the built-in browser to load Google Voice and Google Talk and they worked fine. Of course, this was before they were overhauled into bloated, JS-heavy pages that barely run on non-Chrome mobile browsers.