What's the difference between the various red-dot sights in battlefield 3?

Solution 1:

The Kobra sight is a russian red dot sight, and the Reflex sight is an american red dot sight.

The PKA-S is a russian holographic sight, and the Holographic is an american holographic sight.

• Holographic sights have a more open sight line but you aim down the sights slightly slower than red dot sights.

• Red dot sights are more confined, but aim down the sights the quickest of any scopes.

Holographic (Holo)

Kobra (RDS)

Reflex (RDS)

M145 (3.4x)

PK-A (3.4x)

PKA-S (Holo)

PSO-1 (4x)

All the above screenshots were taken at roughly the same 145 meter position from a capture point, so they should reflect equal distances.

Solution 2:

Just preference. Certain ones are unlocked first on particular weapons. There are no game-play advantages aside from preference. I personally like the Kobra and the Holographic. The PKA-S sits high on the gun and I don't care for that.