With a fixed power and variable power scope of equal quality and build, the fixed power will weigh less, be less expensive to manufacture and have greater optical clarity. Think of comparing a fixed power Mk 4 to a variable power Mk 4. The fixed power has fewer lenses meaning that it will weigh less and have fewer surfaces for the light to pass through. That will theoretically give a better image. It may not be noticeable though.

I happen to like fixed power scopes on my mid range hunting guns. My 358 Winchester wears a 6x and my Savage 99 in 300 Savage has a 4x. For a few years I elk hunted with a 21" barreled 458 Win Mag with a 4x scope and it was an absolute dream to sneak through the alders with! These guns are rarely used where shots will exceed 150 yards, but even with the limited magnification they are perfectly capable of 300 yard shots on deer or elk. I'm not so sure that the 358 is up to killing a deer at 300 yards though! LOL

Andrew