Expect the sniper rifle to be harder to aim with. Standing will cause more movement in the reticle, but crouching allows for more stability. Prone position: not sure if it is or will be implemented.
What most game developers tend to forget is that while looking through a scope, slight movements will cause the image to move rapidly out of sight.
For example, in UT moving the SR while scoped in is slower. But that is not how a scope works. If you scope in on a target, one slight move to the left, right, up or down will cause the target to disappear. Grab a pair of binoculars and you will see what I'm talking about. If you are scoped in, then the mouse sensitivity will increase, instead of decrease.
Sniper rifles will be harder to use and require more skill than the traditional SR.