Actually, reading PDFs is just about the one thing I don't like to do on the Kindle. The Kindle's screen is way too small to show an entire A4 page, and scrolling through the page is awkward (though at least less so on the newer Kindles with a touch screen). You really need something in a format that allows reflowing the text for smaller screens.
The Kindle DX looks like it would be good for reading PDFs that can't reflow the text. No longer made though.