I wondered how it compares to the same subset of SWF, which is another vector format designed with a huge emphasis on size and decode efficiency. The example tiger.svg is 96719, and tiger.tvg is 27522, but I have a tiger.swf which is 21381 and tiger.pdf 77377. It seems to be a little worse than SWF, but much better than SVG and PDF. I agree with the author that SVG is bloated, but not sure making another format is the answer, especially when there's already very good prior art.

(I have written SWF rendering and conversion code before, so I might be biased in saying that it's an example of a very well-designed vector format; too bad Adobe has been trying to kill it off.)