Yeah, IE9 is actually a decent browser. It's pretty much standards compliant (some new HTML/CSS shiny stuff isn't there yet, it's coming in IE10, but I'm happy with that) and I've not found any rendering problems yet
I have however found a couple of problems with some third party javascript libraries (such as ckeditor) but it could just be I'm using old versions. It's on my todo list to look into and fix these, and I expect it's on the todo list of the developers too
Is it worth switching to IE from Chrome? Nah. Although faster than IE8, the IE9 javascript library is still noticeably slower than chrome. I just describe it as "a good default browser". If you're a power user chrome is still the best choice, imo
(Out of interest IE10 is getting there. Lots of new shiny web technologies present and the javascript engine is finally lightning fast. But it's clearly still in very early development and not for everyday use; I've found HTML rendering issues that don't exist anywhere else, and they've stripped out a lot of browser functionality such as the URL bar and the back button type stuff)