I downloaded “Internet Explorer 9 Beta” a couple of weeks ago. I have been consistently using it since then. I must say that the experience so far has been awesome! Browsing is smoother – Windows 7 Integration is nice! – It is much much much much faster than IE8 – It renders most of the websites that I visit quite well.
But programming the browser (using JS) is not quite the same as Chrome or Firefox. But there are easy workarounds, so I dont have too many complaints there. All in all; its very inspiring to see a super-rock-solid browser coming out of Microsoft. I strongly recommend folks to try it out. Its worth it!