They are basically the same thing, but with some differences. There are games that allows players to function both, but both usually serve the same purpose. Prone is under the category of crouch, but in a different level.

Similarities:
- Slows down movement
- Increases accuracy

Differences:
- Iron sight eliminates some peripheral vision. Crouch does not.
- Iron sight can greatly decrease sensitivity movement. Crouch does not.
- Crouch shortens character's height, therefore can hide behind objects or dodge shots. While standing up with iron sights, it does not hide players nor could they dodge. (I'm not saying both at the same time, otherwise that eliminates the purpose of this poll)
- Crouch allows players enter an area that required height. Iron sight while standing up does not.
- Iron sights allow modifications/customization. Crouching increases accuracy on generic weapons. For example, in Call of Duty there's the traditional iron sight, red dot sight, holographic sight, ACOG scope (Or even "Thermal Sight). Games that do not have have Iron sights shows a traditonal gun, sometimes with a scope.

Coming from a CoD gamer, I can tell you already Iron Sights are better.

Crouch does not give you the accuracy needed to snipe.

Iron sights, crouch button placement always makes it harder to crouch micro than iron sights micro. So for effort Ima have to go with iron sights if im legit. If i'm camping then crouch but as far as SEN knows I'm not a douche bag so IRON SIGHTS.

Irunsiets.

That's how Call of Duty is developed. Pay attention to other games, and crouching can be significantly accurate especially to sniping. The Hunting Rifle and Sniper Rifle from Left 4 Dead games is significantly accurate while crouching, and is effective against running hordes of zombies (Which apparently zoom in can be bad during those times).

Technically sniping would be a traditional "zoom in" scope. Yes, while Call of Duty includes attachments such as red dot sight, holograph, ACOG, etc., those are technically NOT iron sight. Snipers usually always use "Scopes", not iron sight. Iron sight is usually looking through a tiny hole that is parallel to a tip of metal at the end of a rifle/gun marking the center.

I've been playing Rainbow Six Vegas Two recently, and crouching is soooo much better in that game.

I've been playing AVA alot recently. Technically, Crouching and Zooming in depends on which guns you're trying to use, and what you're using them for.
Also, if you just crouch at any given time in a firefight, a 'body' shot could become a 'head' shot; which just sucks.

Counter-Strike is really the only game that I really notice where crouching can basically make the difference in a fire fight. But I only play CoD4 and Counter-Strike, and in the former, I almost exclusively look down the iron sights (red dot sight is my favourite). It just really depends on the game in my opinion.

Crouching in most games. Exception being in early stages in the STALKER series, before scopes are available. I see the decrease of sensitivity and view field as a handicap most of the time. I'm used to a rather high sensitivity and rely on turning quick around.

I agree. Also, the slower mobility while standing up allows you to become a perfect shot for opponents.