What would be the advantages of using one over the other. I'm in the process of refactoring/improving a web game (connwars.com) I made a while ago and I was planning on using canvas, but I don't know if svg would work better.
Use canvas if performance is important. Use SVG if it's important to assign functionality to specific graphical elements (as opposed to rolling your own hit detection). See my comment above in this thread for more.
[Usual caveats apply...this is general advice, and I don't know your situation, etc.]
