It's not really the most flexible option. It allows you to make only a fairly limited type of triangle, only pointing in one of eight directions.
If you want compatibility with older versions of IE, use both SVG and VML, depending on the browser (VML for IE 8 and earlier, SVG for everything else). This gives you a lot more flexibility (you can draw any polygon, arc, or bezier curve that you want), and compatibility all the way back to IE 5.
If you want compatibility with older versions of IE, use both SVG and VML, depending on the browser (VML for IE 8 and earlier, SVG for everything else). This gives you a lot more flexibility (you can draw any polygon, arc, or bezier curve that you want), and compatibility all the way back to IE 5.