I have a Cobra XLS
and let me tell you its great!! Light and easy to use. Carrying them is a breeze unless you don't put it together right! Comfortable to sit in for long periods of time. Blends in good. Only Con is the cables can become worn but i just put a rubberized coating on mine when they went to the bare metal.

Grandpa has the Viper so he can sit to climber gettin weaker in his age bt says it does get in the way of bowhunting sometimes but other times it helps for something to lean on to get a shot off.

Its all in what u would prefer and the viper isn't all that much heavier either

In hte end htough i love my Cobra the most nothing to get in your way and nothing to have go wrong for you

12 deer shot and 12 recovered
all credit to pse and nap for spitfire broadheads