We are considering using SVG filters as part of our toolchain, serving the SVG to browsers capable of supporting it, while serving pre-rendered PNGs to other.
One problem we noticed is that the rendering of the filter chains seems to be very inconsistent across renderers. When looking at the "filters01" example from the SVG specification, the rendering looks very different across the tools we tried. Chrome (5.0.307.11) failed to render the image, while other tools (Firefox 3.6, Opera 10.10, Inkscape 0.47, GIMP 2.6.7) render something vaguely similar in style to the picture in the specification, but no two are truly the same.
Is that an issue of under-specification or are the tools just not there? If we would use SVG with filter effects: is there a reference tool that can give us a rendering the way it is intended by the spec?