Actually I did not too long ago as both were high on my list (I bought Thiel 2.3s instead and haven't looked back). The biggest difference between the 9NT and N804 to me was the far better vertical dispersion of the 804 tweeter, and the resultant more-even power response and image stability throughout the room. Surprised me as the tweeters seem very similar. They also seemed freer from the occasional 'spittiness' of the 9 HFs. The mids were full and rich on both, though the 804 bass seemed a tad more defined. Although I listened to both extensively, they were not in the same room on the same day. They would need to be for me to spend the extra $800, but the 804s were notably better to my ear.
