Difference between Holographic and Red Dot sight?

In Call Of Duty Modern Warfare 2, what is the difference between the red dot sights and the holographic sights?

They both look almost the same except for with holographic sometimes I'll see a blue blur surrounding the red dot. What is the actual difference in them though and what makes holographic better?

Solution 1:

I was sure this had been answered before but I couldn't find it...

The holographic provides a small amount of "Zoom" of the sight (not the rest of the world) in comparison to the Red Dot (obviously looking down either or just your "irons" provides some level of Zoom). As a result the "dot" on the Holographic is slightly larger and covers more of your vision. By comparison, the surroundings of the Red Dot are "smaller" and thus occlude less of a crucial part of your screen.

Personally I always prefer the Red Dot.

Solution 2:

Some guns actually make a difference between the two. For instance the M-16 is horribly inaccurate with a red-dot site, but for some reason, intentional or not, it becomes significantly more accurate with a holographic site.

(stand at one side of a room and shoot at the same spot with both sites, you'll notice the spread almost instantly)

My experience has been, more accurate players are often better with the red dot, due to the precision and smaller sight. The holographic however, is often easier for less accurate players due to the larger 'sweet spot'