Today, I was using an SVG as a background image with a CSS filter applied to it to create a drop shadow effect, but ran into a bit of a snag. Looking at the site on a retina display the image looked blurry, the exact problem I was trying to avoid by using SVG. This seems to be a bug in Webkit (not only for SVG but background images in general), but thankfully there is a quick fix!
If you add
-webkit-transform: translateZ(0); to the element with the background image, it should clear it up.
Hopefully someone else finds this helpful!