I haven't heard the 3D however I have heard a pair of Rick's line arrays in my home and at the price point they were unbeatable. Most likely the 3D's are the same. Rick is on of the good guys of audio for sure.
Yes, I heard these at RMAF. Admittedly, the exposure to them was limited, and I've not heard any of Rick's other designs, but the sound of these struck me as being exemplary with a high level of linearity (harmonic accuracy), excellent dimensionality to the stage and nicely detailed. At the $5000 price point, some might think it a bit much given its relatively small size (for a floor stander), but I felt it was one of the top sounding 5 or 6 speakers at the show.
If you can get the opportunity, they are definitely worthy of an audition.
I agree with Dean's assessment. The Selahs were among the best sounding speakers I heard at RMAF, though admittedly I didn't hear very many. But the speakers I did take the time to go hear were ones highly recommended to me by one of my friends who was making the rounds, and the Selahs were among only about a half-dozen or so that made that cut.
In addition to Dean's comments, let me say that I didn't hear them doing anything wrong - which bodes well for long-term enjoyment.
In my opinion, the Selahs 3Ds are quite competitive with some very fine speakers around twice their price.
Speakers that made my friend's and/or my wife's shortlist of recommendations for me to go hear included Intuitive Design, the Selahs, Quad electrostats, Harbeths, and the Pioneer EX speakers. I think there may have been a couple of others but I don't remember what they were now. I didn't make it to the Intuitive Design room, and the Quads weren't hooked up when I went by that room, but I heard the others.