I'm switching from the Harp to the Zone. My Harps, in BT Hard and Tournament Plastics, weren't giving me the fade I needed, especially when I threw the discs harder. I bought an ESP Zone from DiscStalker back when they were selling discs, but I'd considered it too much of a brick and OS. But I gave it another shot, and just threw it harder, and it has really performed well for me. It (the Zone) also performs well on forehand shots as I get better and more comfortable with forehands.
The ESP Zone is great, but I ordered a Titanium Zone, and maaaaannnnn that thing is sweet! Like the Ti Buzzz before it, I put it in the bag to test it out, and it is refusing to come out and sit on the sidelines again.