Reflexed risers give you a shorter brace height for a longer power stroke and more arrow speed, but they are easy to torque. The grip is the pivot point. With reflexed risers, the pivot point is between the ends of the limbs. So you wind up pulling in one direction and pushing in the other, and you have to keep everything in the same plane in order to be acurate. A little twist on the handle will move the forward ends of the limbs a bunch, completely out of alignment between your eye and the target.

Deflexed risers give you a high brace height, so the power stroke is shorter and arrow speed is slower, butit is much more difficultto torque them. The grip/pivot is in front of the forward ends of the limbs, so everythingis being pulled in the same plane. It takes a great deal of effort to move the forward end of the limbs out of alignment with your eye and the target.

Generally, but with some exceptions: Reflexed risers shoot fast arrows, but are more demanding on good form. Deflexed risers shoot slower but are a lot better at letting you get away with minor form mistakes.

Edit: Correction of mistake pointed out by Bols. I really shouldn't post when taking cold medicine. [&:]