Advantages of the telescope:
1-Sighting is in single focal plane (nothing to line up).
2-Light gathering. Might give you more shooting time at first light and dusk.
Disadvantages:
1-1Heavy-You can add about 1# to the weight of the rifle for scope rings and bases. Reduces "fast handling qualities. .
2-Fragile, more parts, etc. (Most scopes today are strong enough as we use them. )
Iron sights have to have the right set up. Must be ghost ring rear/ post front. Not a bead for front. Because of the curve at the top of the bead, it cannot give you as much elevation precision as a post. (Look at military sights.)Just get a wide enough post. Mine iis .100 wide with a white stripe for fast acquisition (See XS Sights).
If you remember your high school physics, you know that when light passes through a circle, the highest intensity of that light is in the center of a circle. The human eye when looking through a circle centers its focus on the place where there is the hightest intensity of light. In this case the center of a circle. Thus, the proper way to use a peep (ghost ring)is to look throught the peep, pick up the front sight and put the front sight on the vital zone of your target. Because of what has been stated above, the front sight will automatically be centered in the center of the post.
Because of this, the size of the aperture is relatively unimportant (within reason). A smaller aperture will give you a sharper focus, but what you really need in the field is a lot of light gathering, which you will get from the larger aperture. (Thre aperture on my rifle is .190),
What you do give up with the peep is light gathering. This might cost you 15 minutes of legal shooting time at the beginning and end of the day.