Dynaudio Sapphire

How does it compare in relation to C4?
My personal experience is that the Sapphire is a fantastic speaker but it's LF limited and from what I understand, outside the US at this point, the allocation is sold out/extremely difficult to source. imo, the only speaker that I've heard that Dynaudio makes that's better is the Temptation/Master.
Do a search for a review of the Sapphire written by fellow Agon member, kthomas.

I bought Kirk's C4's when he upgraded to the Sapphire's and I managed to get a brief, 15 minute listen to them. The Sapphires where not broken in yet, but they sounded quite nice... very coherent, blending nicely across highs, mids and lows. I did not find them to be lacking in bass whatsoever. I would see no burning need for a subwoofer with the Sapphires.

I suspect the Sapphires to be more room friendly than the C4's, as I'm in the process of installing acoustic panels in my room to tame the robustness of my C4's.

The Sapphires are also a smaller, more elegant speaker than the C4's... apt to have a higher WAF. The finish is impeccable and suitable for a formal living room.
I saw a pair just this past week, in one of the darker finishes, at Worldwide Stereo in Montgomeryville, PA. I don't know if they are still for sale or reserved.
With regard to the bass, it just depends on what type of music you listen to. Generally, for most rock, pop, rap and the like I didn't have any issue with the bass. However, when it came to adequately rendering a piano, for example, it was utterly unconvincing imo. Compare the Sapphire's low end to the Temptation or the Focal Alto Utopia Be and it's quite obvious; the Sapphire is simply too light weight.

On a related note, the only real drawback I can see with the Sapphire versus the C4 is soundstage height.
Having owned both the C4s and the Sapphires I feel that they are more similar than different. The C4 due to its sheer size and driver array does lend itself to rather large listening rooms nicely. On the other hand the Sapphire is easier to integrate with more room options and sounds equally incredible. Lack of weight/bass is not a word I would use to describe the Sapphire. I think those whom wait for the professional reviews of the Sapphire to come out before they purchase/or go to listen at their local dealers are going to miss the boat. My understanding is that over 3/4 of the entire production run is already reserved.

(Next Level AV in Chicago Suburbs has them on display with a SimAudio Evolution stack.)
I have owned them both as well - they're both fantastic IMO. Both are excellent on the low-end - I think the Sapphire is even a bit better than the C4 - but I listen to mostly Rock, Blues and Jazz, and not to solo piano, so I'm not sure that I would disagree with Bar81's comments.

I think the Sapphire drivers are somewhat better integrated - just a very coherent speaker. The C4's need to be listened to from a further distance. The C4's also delineate the individual components of the music more distinctly - whether this is a good thing or a bad thing is a matter of taste, but listening to a five-piece rock band on the C4's gives you more of a sense of the five individual players.

The C4's incorporate Dyn's DDC, which helps control radiation patterns and makes this very large speaker work well in less than perfect, huge rooms. The Sapphires do not incorporate this, but are more room friendly to medium-sized rooms.

I think the C4 is a fantastic looking speaker, especially given its size. The Sapphire is a work of art, one of the few components of any ilk that made me want it strongly due to its aesthetics.

I love them both, but would say that they do have distinct differences that could make one preferable to another. And, as Dhaskins says, they are apparently getting close to being sold out. No idea if they'll suddenly decide to do another non-anniversary run of them, or if they'll just do the natural show-up-used thing so many pieces of gear do, but the Sapphires are definitely a special speaker if you're a Dynaudio fan.
I have lived with C2's for a few years now and have Sapphires in for a trial now. No real comparison but I do notice the image height change, what might be reflections formerly handled by the DCC and the extra drivers benefit to the vocals, in particular.

The Sapphires are easier to place and seem suited for low level listening where the C2's just faded away.
The Ivory is very close to the Temptation's birds eye maple finish in colour, its not white at all.

I also hear distinct background vocals that were blended in before, extra instruments or clearer sound that allows the identification of the instrument better.

There is a general sense of ease of performance, they aren't working so hard as to bring attention to themselves, the looks do that on their own.

I think they'll be staying, there is a reason I have been listening to bluegrass and small combo jazz for the past long while, now the whole collection is suitable again.
All the test listening has been rock'n'roll.
Im a Dynaudio dealer, and Ive had the pleasure of having the Sapphires since their release. They are nothing short of amazing in my listening sessions, and the cabinet design is gorgeous. Though the C4s will edge the Sapphires out in terms of dynamics, the Sapphire is a more musical speaker IMO, and much easier to use in a typical room. The C4s NEED a large space to integrate the bass drivers with the rest of the sound.

The Sapphires are reminiscent of the C1s but with more slam and drive. This equates to an almost perfect speaker in my book. This speaker could easily sell for $20K/pair. I think they underpriced the Sapphire to stir up the market a bit. Judging by the fact that close to 3/4 of production has already sold out worldwide, people agree that this is truly a special product. They have confirmed that this will not be another Special 25. Meaning once they sell through, thats it!

I would give the friendly people at Dynaudio a call, and find out if your local dealer has a pair to listen to.

Hope this helps.
I am getting a pair next week, used of course but who cares, the owner took incredible care of them.  I really like the reviews I read here, I know I am a few years late but they helped.