My experience with the 645's is the exact opposite of Travis'. Not having heard his Newforms in his room with his associated equipment, I can't disagree with what he heard.
However, in my room, with my equipment, the 645's are simply phenomenal. The soundstage is as much as 30 ft. deep and wall-to-wall if the recording has the information on it. Imaging is rock solid and very precise. Probably the best imaging I have ever heard. The sweetspot is huge. I can sit directly in front of either speaker 10 ft. away and cannot hear the speaker. The imaging just becomes slightly off center.
The detail is fabulous. You can hear every stick hit cymbals, as well as the skin of drums when they are being struck. The only area that I would nitpick is that pianos don't always sound tonally accurate. But I think this could be atributed as much to my upstream components and to the recording itself as much as to the speakers. Plus, the piano is arguably the most difficult instrument for any speaker to reproduce. I have just ordered a Supratek pre-amp and I am very curious how this may affect tonal accuracy.
I did experience some "phasey-ness" early in the break-in period and also when I experimented with positioning the speakers. In my experience, room interactions were the culprit for the phasey-ness after the break-in period.
As far as tilting the speaker forward, I sit in a standardized chair and I certainly don't feel the need to tilt the speakers forward. When I stand up there is a frequency change, but I do not find it offensive. I usually stay fairly-well planted when I am listening anyway.
The thing that has bothered me more about every other speaker that I have heard is that if you move out of the narrow sweetspot, frequency changes occur and imaging just goes out the window. So I will trade the minor inconvenience of a frequency change when I stand up for the ability to sit virtually anywhere in the horizontal plane and still get an incredible soundstage.
The 645's are not perfect (what speakers are), but I truly believe that they are an incredible bargain.
(BTW, John Meyer is one of the greatest guys that I have had the pleasure of doing business with, audio or otherwise. I have never met him personally, but his customer service has been exceptional.)