Has anybody had experience with the Orions?

I have listened to a pair of Orions. Generally, I've been particularly interested in open baffle spkrs for quite a few years (ever since I listened to "Audio Artistry" spkrs, also designed by Mr Linkwitz) and have frequented the Linkwitz site assiduously.
Following your questions,

they are the closest thing to live music available

I would rather say, they are very close to what is contained in the source material -- what comes out of the phono or the cdp, etc. Having read some of your posts I think you understand the difference. There is an easily perceptible lack of distortion and, an impressive simulation /rendition of dynamics. The dynamics surprised me: the drivers used are quite conventional (OK, selected for their linearity and distortion characteristics, but still off the shelf);
the implementation extremely complex (the xover, 6-8 amplification channels).

Still, the dynamics reminded me of horns -- i.e. far away fm panels.

excellent sub-bass response within an open box

No, they won't go that low. IMO it's a good thing: bass (& sub-bass if necessary) is best implemented independently and separately, away from the main speakers in the listening room.

a very slender and elegant cabinet

There is a good point here: given the sound they produce, the speakers are quite reasonably sized.

Please note that the Orions I heard had the front tweet only. Lately a back tweet has been added.
Cheers

I have heard the speakers in Mr Linkwitz's room and the speakers are excellent. I have owned many speakers in the $10k-$18k range and these (orions) are definately in the top echelon of this group and are priced much less. I believe I would own them if not for the fact that I couldn't then spend gobs of money on trying new electronics and cables. Darn hobby!

These are seriously good speakers and terrific value. I think you would need to spend multiples to get better overall sound ...and you could easily spend multiples and do a lot worse.

I agree very much with the above comment that relative to other/most speakers they do an excellent job of remaining true to the source.

I've built a pair and will be adding the rear tweeter to them in the next 2-3 weeks. I've auditioned numerous other speakers upto 18K—not in my price range, but I did it to find out what 10-20K can get you.

The Orion has the cleanest most detailed bass I've heard. (In my room, it's flat at 20 hz. I reduce the bass usually 4 dB on most jazz and pop recordings, but leave it flat on classical.)

Cleanest, fullest, most transparent midrange I've heard.

Clean, crisp, treble—the best I've heard overall—almost, but not quite as fast as a good ribbon, such as the Piega.

Soundstage, imaging, and transparency throughout the entire audible bandwidth is superlative.

Never thought I'd spend so much on speakers—but these have taught me there's no need to dump megabucks in amplification, cables, and other money pits to get state-of-the-art home audio reproduction.

Not as good as Magico's

There is an interesting thread from Lynn Olson on DIYAudio about open baffle speakers that discusses his ideas for a new speaker as well as some of the the other designs out there like the Orion. It's a huge thread but has been intersting reading.

http://www.diyaudio.com/forums/showthread.php?s=&threadid=100392&perpage=10&highlight=&pagenumber=1