EasyHit light gathering sight has a lot of positive feedback about it. Champion EasyHit can be attached to Remington 870, Benelli Supernova or any other shotgun which has vent rib.
Good sight is extremely important because you use it every time you shoulder a shotgun. There are a lot of sights you can choose for the vented rib barrel. There are magnetic sights, and sights that you attach using a screw or adhesive strip.