I've heard the original Unity kit as well as the Yorkville Unity, including measurements. I've also built two Synergy horns and measured them in the same way as the Unity. Further I've heard the JTR Triple 12 speakers. Short answer: I agree with Brett (A9X) and Roger (Antripodean). I would go for the Unity if you have the chance.
As Ivan said, the Unity or Synergy horns have no special way to bend the laws of physics, however the coax point source aspect is very nice to have. One can have a wider dispersion horn if desired and it can extend a constant beamwidth down very low, while still having a point source. There is a relationship between mouth size, coverage angle and the frequency at which pattern control is lost. Mouth size and coverage angle both lower the pattern loss frequency. So if one has a 60 degree horn, it will not extend a constant beamwidth to a frequency as low as a 90 degree version. However, one also trades off extension. A 90 x 90 horn will tend to lose bottom end extension, but in a Synergy design one can use more mids to overcome this.
Now just for interest, here is a Synergy horn that I designed, measured outdoors in the same way
Notice how it has constant beamwidth down below the graph limits?
The JTR uses the driver as the waveguide and it's not really ideal. The measurements can't be expected to look anywhere near as good in terms of dispersion control.
But how do they sound?
Firstly, the JTR. I've heard them at blistering levels and I have to say they are impressive in their brute force output, even with a regular 100w receiver. One can definitely save funds on amps there! They did not make my ears bleed, although the impression was that they aren't as smooth as the Yorkville. Coax drivers almost always seem to use titanium compression drivers. I consider that a problem, they have a habit of getting harsh.
Now I haven't compared them side by side, but the Unity and Synergy horns in my opinion are clearly better in a couple of areas and inferior in none. Greater clarity, more resolving, more detail and overall smoother sounding. The sound is also a bit more "dry" which I attribute to the directivity. I believe the Yorkville uses a BMS compression driver which is a very nice smooth sounding driver.
Of course Brett, Roger and myself are all biased. Some people may prefer the (expected) wider dispersion of the JTR speakers.
I read about a comparison of a Geddes speaker to a Unity. I'd expect the Geddes to be a bit smoother than the JTR speakers due to the foam and the compression drivers used. The difference then comes down to a bit more midrange detail and a different room interaction. I think the Geddes range would be a more challenging one to go up against. In that contest I think votes could easily end up 50/50, with variation based on preference and priorities.