SVG is supported across all browsers now, but some extremely outdated browsers may still have issues with it. I would say that it is safe to use on your site, but you will likely need to code it directly into your layout.html file, as the logo uploader in the control panel would not accept an SVG file.

The following article outlines the extent of broswer support for SVG and how to use a different image as a fallback: http://svgtutorial.com/svg-browser-support/