Adrian,
if you decide to go with JBL I can say the sound is superb for hi-fi or pro use. Since you make dispersion a priority I think you would like it as the dispersion is incredible(diffraction slot). I built my Pi speakers using 2370's and I love em. You can certainly find more attractive horns, but they look better than other plastic horns they even look better than a lot of metal horns. For the price you mentioned they are a steal. You will not find a better horn(your subjective mileage may vary). *note in my experience 2370's need less compensation than many other horns. A .33 or .22mF should work fine, but that depends on the compression driver. I remember thinking the P Audio had good top end when I considered it a while back. It should do great.
Have fun!
Thomas