Of the TECs you mentioned, I have enjoyed the Trykon the most. I like it much better than the ViperTec. Looking forward to a new Vectrix now.
By the way, if anyone's interested, I have a 28" 70# Trykon fully rigged with a TR Summit sight, TR Drop Zone rest, TR Xchanger stabilizer and the TR Ridge Hunter quiver. The rig is also equipped with an STS system. I'd sell the complete rig for $550.