I have not heard a Helius tonearm (although I hear that they are great with my turntable, a Townshend Rock), but I just upgraded my tonearm from a Moerch DP-6 to their DP-8. And wow. What a great improvement. That DP-8 is a killer arm. Well worth trying to listen to. And if you are in the US, Mehran at Sorasound is fabulous to deal with.
