Test: try to zoom your browser window. What happens? Does the SVG plot zoom with the browser window? Or do scrollbars appear? Do you see flicker when you zoom fast? Does the box display clean text when you move the mouse over the stones?

My test results on Windows 7:

• (+4) Opera 11.52: Zooming: smooth, no flicker, quick response; mouse: quick, reliable response. Overall the best result.
• (+3) Firefox 8.0: Zooming: smooth, no flicker, slow response; mouse: quick, reliable response. Close second after Opera.
• (+1) Chrome 15.0.874: Zooming: smooth, no flicker, slow response; mouse: slow, unreliable, buggy response.
• (-3) Safari 5.1.2: Zooming: no zooming, bad embedding with scroll-bars; mouse with unreadable response.
• (-4) Internet Explorer 9.0.8: Zooming: none; mouse: no response. Total failure.