From Strapy from Remington 870 Forum
Here is the final piece to the 870 express I built for my wife. She chose the Surefire 618LMG over the Eotech because the grip felt better. The Eotech is all Polycarbonate and the Surefire has a bit of a rubber grip.
Also the Eotech depth is much more then the Surefire. As you can see in the pictures, the Surefire rises back up to the mag tube behind the flashlight. The Eotech continues straight back. The Surefire also feels much more solidly built then the Eotech.