I have handled both a Thorn and a D2 Extreme and I'd have to give the nod to the Thorn for the same reasons that BatAction mentioned. It opens nice and smooth and is and is light. The D2 that I handled had such a strong detent that I needed two hands to open it. A lot of people will tell you that a ball detent should be strong, and I'm not disagreeing, but it seemed to be too strong to be practical on the one that I handled.