We updated the PCs at work to IE9, and as far as i've got to use it, it's badly written and has some tearing/displaying issues even with compatability on.
I tried it, and I liked it.
it's light, fast, and simple. Anyways I use firefox yet, cause it gives me more flexibility in the work, and more options to choose.
IE9 is good for starters, and slow computers.
As someone who spends time in developing applications for both IE, Firefox and Chrome, I can tell you that IE 9 has bridged the gap between the three browsers significantly. IE 9 supports the latest and greatest technologies. However, I am weary of using it as my main browser due to its close tie in with Windows Explorer and the Windows OS in general, due to potential viruses and malware. Instead, I used Firefox.
Needeless to say, the answer to your question is suprisingly: Yes, it's pretty good.