Really? I've been pretty happy with IE9, generally 98% of my code works perfectly, it's just a matter of drop shadows, rounded corners, etc that don't work. I honestly want to know what breaks so horribly that it's like coding a site twice.
My memories of IE6 make IE9 seem like a completely different browser. It is somewhat, since they rewrote their rendering engine to fully support CSS 2.1 in IE8.