Downunder,
I had both tonearms on the Teres 340 which accommodate 2 arms and did them under very similar conditions so it was a very fair comparison - i tried to match them very close for this comparison (using both Dynavector XV-1s, same phono cable with Audioquest Leopard and going to the wonderful steelhead which allow me to hook up both tonearms at the same time and with only a simple switch i can go back and forth). Look at my systems setup to get a better idea of my other equipments.
This is my conclusion about the 2 arms:
Phantom: a warmer and laid back sound; tonally sweeter and better midrange and more musical in my opinion. If you crave dynamics, details and live sound, this is not the tonearm for you. With the Koetsu, it's too laid back - i found this arm match better with the Dynavector or the Lyra (tame down these cartridge).
TriPlanar: a very aggressive, live and dynamic arm. Give you all the details you want and very neutral - too neutral in my opinion and can lead to listening fatigue. Very well match with warmer cartridge like the Koetsu.
It's nothing wrong with getting both arm as they are very different in my opinion, i don't think one was better than the other, it's just a matter of taste.
I ended up getting the phantom for a while as i am a midrange freak but when i heard the Kuzma Airline, i am SOLD. Hope that help...
