I scope almost all my rifles. A couple wear peep sights, or have iron back-ups. Too many good reasons not to use a scope. A good, low to medium power scope allows for better target identification (an important safety issue, as well as nice when hunting in states with antler size restrictions, like PA), more accurate placement of your bullet, especially thru heavy brush, can add important minutes to your shooting time before it gets too dark, and are of great benifit to those without perfect eye sight. Over the years, I have taken more then a couple big bucks in thick woods, or poor light, in places like Maine swamps at dusk, or in the thick woods of upstate NY that I would have passed on, or missed outright without a scope. I can only think of one I missed because of a scope, and that was my fault for not keeping the front lens element covered in a driving rain storm. Jumped a nice buck, and it looked like a kalydascope when I tried to aim because of the water. Smart hunters use lens cloths that are available that reduce or eliminate fogging, and cause water to bead up.
A scope may alter the balance of some rifles, or look out of place, but that is a small price to pay, in my opinion. Iron sights, and especially peeps can be quite accurate, under the right circumstances, and god bless the guys who only shoot irons, and hit their deer between the eyes at 300 yards, every year, without fail. But for most users, an optical sight just offers too many benifits to ignore.
Larry