Check out the review at High Fidelity. I have the 9700 and 8100 and I'd generally agree with his comparison assuming the 9900 and 9700 are similar. High Fidelity
also checkout singaporehifi blogspot. I'm not allowed to post links yet but the most recent update is about the 9900 and he compares it to the 8100 and 9700
I'm not sure I agree with his conclusion about the 8100 versus the 9900 (and 9700 if they are similar) but nothing he says dissuades me from wanting to hear the 9900