I have been using Internet Explorer 9 since the early beta on my production laptop. I have also been using it on a few other machines that I use on a daily basis. I had a few issues early on in the beta that required me to use compatibility mode on a few sites, but those were resolved early on. With the official release of IE9 to the web, I have now updated all of my machines and they are all working great!
You can grab the official release of Internet Explorer 9 here!