Know that every weapon does knock-back to some degree.
The rule of thumb is: more damage, more knock-back.
Reliable in team-fights as the splash damage can hit multiple people, and for spamming down hallways to discourage people from running through.
Knock-back stacks very quickly after taking damage which makes this very useful for controlling other players' movement, especially with multiple people focusing one player.
Large champions will usually eat damage(see Clutch) from the LG faster since they are just simply large targets to hit.
Useful for doing damage from afar and cutting down the enemies HP/AP stack.
Good for doing chip damage or finishing off enemies with low health stacks.
Avoid using this as a "main" weapon, however it does a critical role in doing damage to your enemies so use wisely.
Projectiles from this weapon do move rather slow but when upgarded can do massive damage, especially in the form of spam.
Generally avoid using this as a "main" weapon but it still is capable for helping team-mates since damage will stack up very fast with this weapon.
General idea is short range, slow fire, big damage. Be wary if you play a larger character because you can and will take massive damage from both shotguns.
Also reliable for finishing off near-dead enemies at short to medium range.
Good for zoning and providing large are of effect in team fights.
Currently does large amounts of reliable damage for assisting team-fights but not directly doing damage.